ImmunologyToday,vol. 8, No. 1, 1987
What would impel 190 different laboratories to work together in the performance of more than i50 000 assays to characterize about 800 antibodies? Participants in the 3rd International Workshop on Human Leukocyte Differentiation Antigens* generally shared the conviction that such cooperative effort has the potential to bring order out of the chaos of molecules described on the surface of human leukocytes. The meeting had two components; a summary/synthesis of the results of the workshop and a more conventional scientific meeting with plenary presenta~)ons and workshop~ ,~ocused on r~search related to human leukocyte differentiation antigens. Among the 'breaking news stories' in the meeting were the cloning of CD1 (C. Milstein, Cambridge), CD2 (R. Sewall, London),. Lyt 3 (P. Johnson, Oxford) and the LFA-1 beta chain (CDw18) (K. Kishimoto, Boston and A. Law, Oxford), the characterization of apparently T cell-specific calcium channels (E. Reinherz, Boston), and the description of a second putative IL-2 receptor which creates high affinity IL-2 binding sites by cooperativity with CD25 (Tac) (T. Waldmann, Bethesda). But the most newsworthy aspect of the meeting is the colossal collaboration and the The workshop's success stems in large part from the fine organization mobilized by the president (Milstein), and the chairman (A. McMichael, Oxford). But particular credit in the workshop goes to statisticians D. Spiegelhalter, W. Gilks and S. Cobbold (Cambridge) who made the data analysis not only intelligent but also 'user friendly'. They introduced new approaches which showed similarities between monoclonal antibodies (mAb! which had appeared different due only to differences in their titer or affinity. As their analysis evolved, it transcended the traditional boundaries between mAb apparently specific for T cells, B cells, etc., and detected patterns not previously well appreciated. By exploiting the growing power and portability of personal computers, they made do-it-yourself analysis possible. At the meeting, participants crowded around several computers *Theworkshop,conductedduringthe lastyear,was summarized at a conference in Oxford, 21-26 September1986. ((~) 1987. Ll'.,evierScience Publ~',her', B V. Am,-,b,rdam
0167
Characterizationof humanleukoc e differentiationantigens fromSlephenShaw to get customized analysis of data relevant to their particular mAb or cells. There are plans to 'publish' a version of the proaramsMatabase within the next 6 months so that individuals can rapidly make presumptive assignment of the specificity of a new mAb by comparison of its reactivity pattern with the 800 plus mAb from the workshop. What were the accomplishments of the workshop? The easiest to summarize relate to the standardization of nomenclature for leukocyte cell differentiation molecules, which was the raison d'etre of the workshop. Agreement was reached on clusters of mAb which define 18 'new' celi surface molecules, and provisional recommendations for nomenclature for them were made. Together with the results of 2 previous workshops (Paris 1980 and Boston 1984), this swells the roster of cluster determinant (CD) groups and subgroups to 50 (see Table 1). The CD nomenclature is only gradually and unevenly replacing prior ~diosyncratic nomenclatures: I have the impression thaL this reflects, in part, a sanguine belief by workshop organtzers that adoption of the nomenc'0ature will result more readily from a general perception of need for a unif~,rm nomenclature than from 'jawbon!ng' or editorial fiat. It is apparent that the need is less for a new nomenclature for molecules like LFA-1 (dubbed CDI la) and gpllb/llla (CDw41) than for other molecules for which a de farto standard nomenclature has not ar;sen. The workshop meeting ,~as by no means a dry scholarly exercise in molecular cataloguing. In practical terms the nomenclature is only a small part of the larger role of the workshop in bringing together an impressive array of mAb, characterizing their relationship to each other, and making them available as shared (but by no means 'common') reagents for a diversity of studies. The power of joint analysis is illustrated by studies of a molecule variously referred to as 'Leukocyte Common Antigen', T200, or B220 but now entitled CD45. This molecule, which is expressed in high density on cells 4glc],87/$02 00
of hematopoietic lineage and generally immunoprecipitated as 4 bands (at' 220, 205, 190 and 180kDa), turns out to be the antigen recognized by 53 differer~t workshop mAb. 'Conventional' CD45 mAb (n=:34) bind determinants of all four molecular weights and bind to all T cells, B cells, granulocytes and m~ crophages. In contrast, the 'restricted' mAb, designated CD45R (n=19), all recognize only the 220kDa and 205kDa bands and have the pecu!iar property of being expressed only on subsets of T cells, B cells and monocytes. Almost half of these restricted mAb were not appreciated to be in this category by the contributing laboratory; indeed one of those mAb (2H4) has generally been viewed as a marker of T-cell subsets and distinguishes functional subsets of T cells, while others were thought to be B-cell specific mAb. However, careful analysis of data in the workshop permitted their reassignment to the CD45 cluster and facilitated further analysis. Biochemical analyses by F. Sanchez-Madrid (Madrid) not only confirmed the relationship outlined above between 'conventional' and 'restricted' mAb but also added two new patterns of reactivity of unique mAb among the huge panel: one reactive with only the lowest molecular weight band and another with the highest three. Different approaches to epitope mapping by G. Hale (Cambridge) and R. Dalchau (E. Grinstead) showed close concordance regarding at least five epitopes seen by the conventional CD45 mAb anJ two epitopes seen by the mAb against restricted forms of that molecule. These studies fit well with molecular genetic studies reviewed by I. Trowbridge (La Jolla) showing that a single T200 gene produces four different forms of the molecule by alternate splicing which accounts for differences of up to 150 amino acids in the amino terminus of the molecule. ]he remarkable number of mAb, variety of approaches, consistency of results, and thoroughness of analysis leaves no doubt that this workshop will ~>e a milestone in the understanding of the leukocyte com-
Immunology Today. vol. 8, No. 1, 1987
Table 1. CD antigens 1986
Antigen
Formerly
Mul. '~;~(kr)a)
Distribution
CDla CDlb CDlc CD2 CD3 CD4 CD5 CD6 CD7 CD8 CD9 CD10 CD11a CD11b CD11c CDw12 CD13 CD14 CD15 CD16 CD17 @i8 CD19 CD20 CD21 CD22 CD23 CD24 CD25 CDw26 CD27 CD28 CDw29 CD30 CD31 CDw32 CD33 CD34 CD35 CD36 CD37 CD38 CD39 CDw40 CDw41 CDw42 CD43 CD44 CD45 CD45R
CD1 CDI CD1
49 45 43 50 20,26 60 67 120 40 32 24 100 180(95) 160(95) 150(95)
thymocytes (Langerhans'cells) thymocytes thymocytes T cells cells subset cells cells cells subset monocytes, pre-B, platelets pre-B, aCALL leucocytes monocytes, granulocytes monocytes (granulocytes)
150
granulocytes, monocytes monocytes (granulocytes)~FDRC granulocytes (monocytes) granulocytes granulocytes, monocytes, platelets leucocytes B cells B cells, FDRC B cells, FDRC B cells B subset, FDRC B cells, granulocytes activated T cells activated T cells T cells, plasma cell T subset T subset activated T cells, activated B cells monocytes, granulocytes, platelets (T cells)(bone marrow) monocytes, granulocytes, platelets, B cells myelogenous leukaemia myeloid and lymphoblastic leukaemia granulocytes, monocytes, FDRC monocytes, platelets B cells restricted multiple lineages B cells, macrophages,vessels B cells, carcinomas, ciRC platelets platelets T cells, granutocytes, red cells, brain T cells, pre-B, brain, granulocytes leucocytes B cells, T subset, granulocytes, monocytes
CDw18 CD11
Comments
Fc,R
mnnnr~d..~< nr~ml nr~m,c nl~'~l~tc . . . . . . . . . . , ~lu ~.~. i,,. , . J
CDw13 CDw14 CDwl 5
50-60 - -
95 95 35 140 135 45
45,55,65 55 130 120->55 44 135 130-140 40 67 115 220 85 40-45 45 80 50 95 65-85 220,205,190,180 220,205
X hapten FcRro lactosyl-ceramide LFA-B C3dR
IL-2R p44 (9.3) 4B4 Ki-! ?gplla ?FcR, CR1 gplV
gpllb/llla gplb
T200, LCA restricted T200 2H4 etc
aCALL= commontypeacutelymphoblasticleukaemia. DFDRC= folliculardendriticreticulumcells. Clnr
.,~.
. . . .
-in~e,i-Jinit6.~,,7,
-, I-~- L, I L U. .l U. .l.I.I. . .
L~'iI~,
Weakreactionsshownin parentheses.Molecuar weightsin kDa,all reducedexceptCD27125 non-reduced-> 55 reduced. Notethatthe nomenclatureCDla,b,c,CD1la,b,c,CD18,CD27-45Ris provisional.It hasbeenrecommendedby the workshopnomenclaturecommitteebut still hasto beapprovedby IUIS-WHO. mon antigen and CD45 mAb reactive with it. The functional data on CD45 were fragmentary but no less interesting. H. Tighe (Cambridge) reported that
CD45 mAb powerfully inhibit T-cell-mediated killing if they are crosslinked on the T cell with anti-immunoglobulin. J. Martorell (Barcelona) showed that CD45 mAb
enhance CD3-induced T-cell triggering. K. Moore (Southampton) confirmed and extended findings that mAb against the restricted form distinguish functional subsets of T
ImmunologyToday,vol. 8, No. 1, 1987
cells. Thus, although this molecule is been the mainstay of previous work- DiSanto, New York and P. Kavathas, by no means lineage-restricted, it is shop analysis: uniqueness of tissue New Haven). Is it the human analog critically involved in lineage-specific distribution. For example the cluster- of Lyt3? functions of lymphoid cells. ing of CD13 mAb was dramatically It is futile in this allotted space to Screening mAb for binding to cell seen in idiosyncracies of their im- try to summarize the multitude ,,f lines transfected with defined genes munohistology, e.g. 'lacy' processes other observations emerging frorq was an important new technology of subepidermal macrophages and this meeting whose purview inexploited in this workshop. This was strong staining of bile canaliculi. cluded T cells, B cells, myeloid cells, particularly productive for character- Transfectant screening does have activation antigens, and even ization of the 'myeloid panel' of complexities. Studies on tl~e myeloid ptatelets. However, the conference mAb, under the leadership of N. mAb conducted on two cell lines organizing committee will write deHogg (London). Transfectants ex- transfected with the CD14 gene tailed summaries which will be pubpressing six different genes, from the demonstrated that only an unex- lished by Oxford University Press in laboratories of T. Look (Memphis) plained subset of the CD14 mAb Spring 1987. The next workshop will and S. Goyert (New York), figured bound to the gene transfected into be under the direction of W. Knapp prominently in the consolidation of murine NIH3T3 cells whereas all (Vienna) and several German colinformc,ion about two previous clus- bound to monkey (COS-7) cells ex- laborators. ters (CD13 and CD14) and the for- pressing CD14. Another promising mulation of four new clusters. For I:~ad from transfectant screening was some clusters of mAb, transfectant the identification of a unique mAb screening was critical in establishing deemed to be CD8 in all respects Stephen Shaw is at the ImmunologyBranch, similarity. In other cases it provided other than its ability to bind cell National Cancer Institute, National Institutes validation of the approach which has lines transfected with CD8 gene (J. of Health, Bethesda,MD 20892, USA
Much of current research in autoimmunio/ focuses on the role of major histocompatibility (MHC) antigens in the disease process and the relevance of chemicals as etiological agents. A recent workshop* dealt with both topics.
Histocompa|ibility antigens and c emical reactivity in autoimmunJly from HubertKolb, KlausV. Toykaand ErnstGleichmann
Class I1 MHC (la) antigens are of recurrent bacterial infections but can much interest in the study of the survive viral infections. One possible induction and pathogenesis of interpretation of thk observation is ornan-~n~cifir fnr .Llldl --j .... . . . . . . . ~ . . tn . . .m .m .~ . .Jnity, . . . . . .CldS~ .. .... ii MHC an tig ens oT~en two reasons. Firsdy, the search for are not essential for viral defense important disease susceptibility mechanisms because adequate viral genes has most often led to the class antigen presentation might occur via II region. Secondly, the aberrant ex- class I MHC antigens. A definite conpression of class II MHC antigens in clusion will be difficult until it is target organs undergoing (auto-) known how many genes other than immune-mediated attack has been those for la antigens are blocked regarded as a possible key to the from transcription in these children. initiation of the process of orgdn It is possible that class II MHC antispecific autoimmunity. gens may be more important for What do we know, generally humoral immunity than for the genspeaking, about the relevance of la eration of cytotoxic lymphocytes. antigens in humoral and cellular im- This accords with a recent view that munity in vivo? Some first insights there are two antigen presentation have been gained from the study of systems 1, one for exogenous procertain children who are almost teins (employing class II MHC anticompletely deficient in class II MHC gens) and one for endogenous celluantigen expression and specific lar proteins (employing class I MHC mRNA from early infancy. Their antigens). maior symptoms are agammaglobulinaemia (owing to defective B- Altered MHC antigen expression lymphocyte function) and failure to It seems important, therefore, to thrive (M. Hadam, Hannover; H. study aberrant or enhanced expresPeter, Freiburg). Tilese children have sion not only of class II but also of class I MHC anti0ens in target *TheThirdDOsseldorfWorkshopon Autoimmunity, organs. In pancreatic islets enhanced organizedbyE.Gleichmann,H.KolbandK.V.Toyka, expression of class I MHC antigens can be observed during the developwasheldon6-7 October,1986. IV
(.{-) 1987, Elsevier Scmnce Pubhshers B V , Amsterdam
,v,
0167
4 9 1 9 / 8 7 / $ 0 2 O0
ment of diabetes first along endothelia and later on all cell types in the islet and on neighbouring exocrine ceils (G. Bottazzo, London; G. Kantwerk, DOsseldorf). la antigens also appear along endothelia of larger vessels and on infiltrating cells. The aberrant expression of class II MHC antigens on target insulin-producing beta islet cells has been disputed for so~ne time. In vivo, positive results by immunocytochemical methods were reported by Bottazzo for human tissue and by W. Muller-Ruchholz and K. Ulrichs (Kiel) for rat islets. In Kiel, la positivity was found only when using antibody 29A1-HT. In the brain, during the induction of experimental autoimmune encephalomyelitir (EAE) it is not endothelial but perivascular cells (pericytes) and astrocytes which turn strongly la positive. Oligodendrocytes which synthesize the target structure (myelin) do not express la antigens in response to gamma interferon (IFN-~) but may show more class I MHC antigen during viral infection 2. In the peripheral nervous system, Schwann cells producing the target structure (myelin sheath) for experimental autoimmune neuritis
What would impel 190 different laboratories to work together in the performance of more than i50 000 assays to characterize about 800 antibodies? Participants in the 3rd International Workshop on Human Leukocyte Differentiation Antigens* generally shared the conviction that such cooperative effort has the potential to bring order out of the chaos of molecules described on the surface of human leukocytes. The meeting had two components; a summary/synthesis of the results of the workshop and a more conventional scientific meeting with plenary presenta~)ons and workshop~ ,~ocused on r~search related to human leukocyte differentiation antigens. Among the 'breaking news stories' in the meeting were the cloning of CD1 (C. Milstein, Cambridge), CD2 (R. Sewall, London),. Lyt 3 (P. Johnson, Oxford) and the LFA-1 beta chain (CDw18) (K. Kishimoto, Boston and A. Law, Oxford), the characterization of apparently T cell-specific calcium channels (E. Reinherz, Boston), and the description of a second putative IL-2 receptor which creates high affinity IL-2 binding sites by cooperativity with CD25 (Tac) (T. Waldmann, Bethesda). But the most newsworthy aspect of the meeting is the colossal collaboration and the The workshop's success stems in large part from the fine organization mobilized by the president (Milstein), and the chairman (A. McMichael, Oxford). But particular credit in the workshop goes to statisticians D. Spiegelhalter, W. Gilks and S. Cobbold (Cambridge) who made the data analysis not only intelligent but also 'user friendly'. They introduced new approaches which showed similarities between monoclonal antibodies (mAb! which had appeared different due only to differences in their titer or affinity. As their analysis evolved, it transcended the traditional boundaries between mAb apparently specific for T cells, B cells, etc., and detected patterns not previously well appreciated. By exploiting the growing power and portability of personal computers, they made do-it-yourself analysis possible. At the meeting, participants crowded around several computers *Theworkshop,conductedduringthe lastyear,was summarized at a conference in Oxford, 21-26 September1986. ((~) 1987. Ll'.,evierScience Publ~',her', B V. Am,-,b,rdam
0167
Characterizationof humanleukoc e differentiationantigens fromSlephenShaw to get customized analysis of data relevant to their particular mAb or cells. There are plans to 'publish' a version of the proaramsMatabase within the next 6 months so that individuals can rapidly make presumptive assignment of the specificity of a new mAb by comparison of its reactivity pattern with the 800 plus mAb from the workshop. What were the accomplishments of the workshop? The easiest to summarize relate to the standardization of nomenclature for leukocyte cell differentiation molecules, which was the raison d'etre of the workshop. Agreement was reached on clusters of mAb which define 18 'new' celi surface molecules, and provisional recommendations for nomenclature for them were made. Together with the results of 2 previous workshops (Paris 1980 and Boston 1984), this swells the roster of cluster determinant (CD) groups and subgroups to 50 (see Table 1). The CD nomenclature is only gradually and unevenly replacing prior ~diosyncratic nomenclatures: I have the impression thaL this reflects, in part, a sanguine belief by workshop organtzers that adoption of the nomenc'0ature will result more readily from a general perception of need for a unif~,rm nomenclature than from 'jawbon!ng' or editorial fiat. It is apparent that the need is less for a new nomenclature for molecules like LFA-1 (dubbed CDI la) and gpllb/llla (CDw41) than for other molecules for which a de farto standard nomenclature has not ar;sen. The workshop meeting ,~as by no means a dry scholarly exercise in molecular cataloguing. In practical terms the nomenclature is only a small part of the larger role of the workshop in bringing together an impressive array of mAb, characterizing their relationship to each other, and making them available as shared (but by no means 'common') reagents for a diversity of studies. The power of joint analysis is illustrated by studies of a molecule variously referred to as 'Leukocyte Common Antigen', T200, or B220 but now entitled CD45. This molecule, which is expressed in high density on cells 4glc],87/$02 00
of hematopoietic lineage and generally immunoprecipitated as 4 bands (at' 220, 205, 190 and 180kDa), turns out to be the antigen recognized by 53 differer~t workshop mAb. 'Conventional' CD45 mAb (n=:34) bind determinants of all four molecular weights and bind to all T cells, B cells, granulocytes and m~ crophages. In contrast, the 'restricted' mAb, designated CD45R (n=19), all recognize only the 220kDa and 205kDa bands and have the pecu!iar property of being expressed only on subsets of T cells, B cells and monocytes. Almost half of these restricted mAb were not appreciated to be in this category by the contributing laboratory; indeed one of those mAb (2H4) has generally been viewed as a marker of T-cell subsets and distinguishes functional subsets of T cells, while others were thought to be B-cell specific mAb. However, careful analysis of data in the workshop permitted their reassignment to the CD45 cluster and facilitated further analysis. Biochemical analyses by F. Sanchez-Madrid (Madrid) not only confirmed the relationship outlined above between 'conventional' and 'restricted' mAb but also added two new patterns of reactivity of unique mAb among the huge panel: one reactive with only the lowest molecular weight band and another with the highest three. Different approaches to epitope mapping by G. Hale (Cambridge) and R. Dalchau (E. Grinstead) showed close concordance regarding at least five epitopes seen by the conventional CD45 mAb anJ two epitopes seen by the mAb against restricted forms of that molecule. These studies fit well with molecular genetic studies reviewed by I. Trowbridge (La Jolla) showing that a single T200 gene produces four different forms of the molecule by alternate splicing which accounts for differences of up to 150 amino acids in the amino terminus of the molecule. ]he remarkable number of mAb, variety of approaches, consistency of results, and thoroughness of analysis leaves no doubt that this workshop will ~>e a milestone in the understanding of the leukocyte com-
Immunology Today. vol. 8, No. 1, 1987
Table 1. CD antigens 1986
Antigen
Formerly
Mul. '~;~(kr)a)
Distribution
CDla CDlb CDlc CD2 CD3 CD4 CD5 CD6 CD7 CD8 CD9 CD10 CD11a CD11b CD11c CDw12 CD13 CD14 CD15 CD16 CD17 @i8 CD19 CD20 CD21 CD22 CD23 CD24 CD25 CDw26 CD27 CD28 CDw29 CD30 CD31 CDw32 CD33 CD34 CD35 CD36 CD37 CD38 CD39 CDw40 CDw41 CDw42 CD43 CD44 CD45 CD45R
CD1 CDI CD1
49 45 43 50 20,26 60 67 120 40 32 24 100 180(95) 160(95) 150(95)
thymocytes (Langerhans'cells) thymocytes thymocytes T cells cells subset cells cells cells subset monocytes, pre-B, platelets pre-B, aCALL leucocytes monocytes, granulocytes monocytes (granulocytes)
150
granulocytes, monocytes monocytes (granulocytes)~FDRC granulocytes (monocytes) granulocytes granulocytes, monocytes, platelets leucocytes B cells B cells, FDRC B cells, FDRC B cells B subset, FDRC B cells, granulocytes activated T cells activated T cells T cells, plasma cell T subset T subset activated T cells, activated B cells monocytes, granulocytes, platelets (T cells)(bone marrow) monocytes, granulocytes, platelets, B cells myelogenous leukaemia myeloid and lymphoblastic leukaemia granulocytes, monocytes, FDRC monocytes, platelets B cells restricted multiple lineages B cells, macrophages,vessels B cells, carcinomas, ciRC platelets platelets T cells, granutocytes, red cells, brain T cells, pre-B, brain, granulocytes leucocytes B cells, T subset, granulocytes, monocytes
CDw18 CD11
Comments
Fc,R
mnnnr~d..~< nr~ml nr~m,c nl~'~l~tc . . . . . . . . . . , ~lu ~.~. i,,. , . J
CDw13 CDw14 CDwl 5
50-60 - -
95 95 35 140 135 45
45,55,65 55 130 120->55 44 135 130-140 40 67 115 220 85 40-45 45 80 50 95 65-85 220,205,190,180 220,205
X hapten FcRro lactosyl-ceramide LFA-B C3dR
IL-2R p44 (9.3) 4B4 Ki-! ?gplla ?FcR, CR1 gplV
gpllb/llla gplb
T200, LCA restricted T200 2H4 etc
aCALL= commontypeacutelymphoblasticleukaemia. DFDRC= folliculardendriticreticulumcells. Clnr
.,~.
. . . .
-in~e,i-Jinit6.~,,7,
-, I-~- L, I L U. .l U. .l.I.I. . .
L~'iI~,
Weakreactionsshownin parentheses.Molecuar weightsin kDa,all reducedexceptCD27125 non-reduced-> 55 reduced. Notethatthe nomenclatureCDla,b,c,CD1la,b,c,CD18,CD27-45Ris provisional.It hasbeenrecommendedby the workshopnomenclaturecommitteebut still hasto beapprovedby IUIS-WHO. mon antigen and CD45 mAb reactive with it. The functional data on CD45 were fragmentary but no less interesting. H. Tighe (Cambridge) reported that
CD45 mAb powerfully inhibit T-cell-mediated killing if they are crosslinked on the T cell with anti-immunoglobulin. J. Martorell (Barcelona) showed that CD45 mAb
enhance CD3-induced T-cell triggering. K. Moore (Southampton) confirmed and extended findings that mAb against the restricted form distinguish functional subsets of T
ImmunologyToday,vol. 8, No. 1, 1987
cells. Thus, although this molecule is been the mainstay of previous work- DiSanto, New York and P. Kavathas, by no means lineage-restricted, it is shop analysis: uniqueness of tissue New Haven). Is it the human analog critically involved in lineage-specific distribution. For example the cluster- of Lyt3? functions of lymphoid cells. ing of CD13 mAb was dramatically It is futile in this allotted space to Screening mAb for binding to cell seen in idiosyncracies of their im- try to summarize the multitude ,,f lines transfected with defined genes munohistology, e.g. 'lacy' processes other observations emerging frorq was an important new technology of subepidermal macrophages and this meeting whose purview inexploited in this workshop. This was strong staining of bile canaliculi. cluded T cells, B cells, myeloid cells, particularly productive for character- Transfectant screening does have activation antigens, and even ization of the 'myeloid panel' of complexities. Studies on tl~e myeloid ptatelets. However, the conference mAb, under the leadership of N. mAb conducted on two cell lines organizing committee will write deHogg (London). Transfectants ex- transfected with the CD14 gene tailed summaries which will be pubpressing six different genes, from the demonstrated that only an unex- lished by Oxford University Press in laboratories of T. Look (Memphis) plained subset of the CD14 mAb Spring 1987. The next workshop will and S. Goyert (New York), figured bound to the gene transfected into be under the direction of W. Knapp prominently in the consolidation of murine NIH3T3 cells whereas all (Vienna) and several German colinformc,ion about two previous clus- bound to monkey (COS-7) cells ex- laborators. ters (CD13 and CD14) and the for- pressing CD14. Another promising mulation of four new clusters. For I:~ad from transfectant screening was some clusters of mAb, transfectant the identification of a unique mAb screening was critical in establishing deemed to be CD8 in all respects Stephen Shaw is at the ImmunologyBranch, similarity. In other cases it provided other than its ability to bind cell National Cancer Institute, National Institutes validation of the approach which has lines transfected with CD8 gene (J. of Health, Bethesda,MD 20892, USA
Much of current research in autoimmunio/ focuses on the role of major histocompatibility (MHC) antigens in the disease process and the relevance of chemicals as etiological agents. A recent workshop* dealt with both topics.
Histocompa|ibility antigens and c emical reactivity in autoimmunJly from HubertKolb, KlausV. Toykaand ErnstGleichmann
Class I1 MHC (la) antigens are of recurrent bacterial infections but can much interest in the study of the survive viral infections. One possible induction and pathogenesis of interpretation of thk observation is ornan-~n~cifir fnr .Llldl --j .... . . . . . . . ~ . . tn . . .m .m .~ . .Jnity, . . . . . .CldS~ .. .... ii MHC an tig ens oT~en two reasons. Firsdy, the search for are not essential for viral defense important disease susceptibility mechanisms because adequate viral genes has most often led to the class antigen presentation might occur via II region. Secondly, the aberrant ex- class I MHC antigens. A definite conpression of class II MHC antigens in clusion will be difficult until it is target organs undergoing (auto-) known how many genes other than immune-mediated attack has been those for la antigens are blocked regarded as a possible key to the from transcription in these children. initiation of the process of orgdn It is possible that class II MHC antispecific autoimmunity. gens may be more important for What do we know, generally humoral immunity than for the genspeaking, about the relevance of la eration of cytotoxic lymphocytes. antigens in humoral and cellular im- This accords with a recent view that munity in vivo? Some first insights there are two antigen presentation have been gained from the study of systems 1, one for exogenous procertain children who are almost teins (employing class II MHC anticompletely deficient in class II MHC gens) and one for endogenous celluantigen expression and specific lar proteins (employing class I MHC mRNA from early infancy. Their antigens). maior symptoms are agammaglobulinaemia (owing to defective B- Altered MHC antigen expression lymphocyte function) and failure to It seems important, therefore, to thrive (M. Hadam, Hannover; H. study aberrant or enhanced expresPeter, Freiburg). Tilese children have sion not only of class II but also of class I MHC anti0ens in target *TheThirdDOsseldorfWorkshopon Autoimmunity, organs. In pancreatic islets enhanced organizedbyE.Gleichmann,H.KolbandK.V.Toyka, expression of class I MHC antigens can be observed during the developwasheldon6-7 October,1986. IV
(.{-) 1987, Elsevier Scmnce Pubhshers B V , Amsterdam
,v,
0167
4 9 1 9 / 8 7 / $ 0 2 O0
ment of diabetes first along endothelia and later on all cell types in the islet and on neighbouring exocrine ceils (G. Bottazzo, London; G. Kantwerk, DOsseldorf). la antigens also appear along endothelia of larger vessels and on infiltrating cells. The aberrant expression of class II MHC antigens on target insulin-producing beta islet cells has been disputed for so~ne time. In vivo, positive results by immunocytochemical methods were reported by Bottazzo for human tissue and by W. Muller-Ruchholz and K. Ulrichs (Kiel) for rat islets. In Kiel, la positivity was found only when using antibody 29A1-HT. In the brain, during the induction of experimental autoimmune encephalomyelitir (EAE) it is not endothelial but perivascular cells (pericytes) and astrocytes which turn strongly la positive. Oligodendrocytes which synthesize the target structure (myelin) do not express la antigens in response to gamma interferon (IFN-~) but may show more class I MHC antigen during viral infection 2. In the peripheral nervous system, Schwann cells producing the target structure (myelin sheath) for experimental autoimmune neuritis
