336

Immunology Today, vol. 4, No. 12, 1983

of isotype expression may become possible by this means. CHARLES A. JANEWAY, JR Department of Pathology, Yale UniversitySchoolof Medicine, New Haven, CT 06510, USA.

References 1 Perlmutter, P. M., Hamburg, D., Briles, D. E. et al. (1978)J. Immunol. 121,566 2 Morshan, G., Berek, C. and Miller, J. F. A. P.

The value of theoretical immunology SIR, J u d i t h R a e L u m b (Immunol. Today, 1983, Vol. 4, pp. 209-210) appears to confuse theoretical with mathematical immunology. She contends that experimental immunologists pay little atten-

(1983) Nature (London) 301, 720 3 Dzierzak, E. A., Rosenstein, R. W. and Janeway, C. A., Jr (1981)J. Exp. Med. 154, 1432 4 Herzenberg, L. A., Okumura, K. and Metzler, C. M. (1975) Transplant Rev. 27, 57 5 Herzenberg, L. A., Okumura, K., Cantor, H. et al. (1976)J. Exp. Med. 144, 330 6 Janeway, C. A., Jr ( 1981) in Strategiesof Immune Regulation (Sercarz, E. E. and Cunningham, A. J., eds), pp. 179-198, AcademicPress, New York 7 Rosenberg, J. and Asofsky, R. (1981) Eur. J. ImmunoL 11, 705 8 Bottornly, K., Janeway, C. A., Jr, Mathieson,

tion to work in theoretical immunology. She ignores the fact that tremendous advances in immunology have been based upon theoretical work. Two examples include Burnet's clona! selection theory and J e r n e ' s network hypothesis. It appears to be true that experimental immunologists pay little attention to the work of mathematical immunologists.

9 10 11 12 13 14

B.J. and Mosier, D. E. (1980) EurJ. Immunol. 10, 159 Hetzelberger, D. and Eichmann, K. (1978) Eur. J. ImmunoL 8, 846 Kimoto, M., Kishimoto, T., Noguchi, S. et al. (1977)J. Immunol. 118, 1840 Ishizaka, K. and Ishizaka, T. (1978) Immunol Rev. 41, 109 Kawanishi, H., Saltzman, L. E. and Strober, W. (1983)J. Eap. Med. 157, 433 Kijono, H., McGhee,J. R., Mostellar, L. M. et at. (1982)J. Exp. Meat. 156, 1115 Rohrer, J. w., Gershon, R. K., Lynch, R. G. and Kemp, J. D. (1983)J. Mol. Cell. Imraunol. 1, 50

However, mathematical immunologists appear to largely communicate amongst themselves and to do very little thorough investigation of the experimental systems they wish to model. RALPH C. GIORNO Division of Clinical Immunology, Department of Medicine, School of Medicine, University of Colorado Health Sciences Center, Denver, CO 80262, USA.

* ** This letter was sent to Professor Lumb, who replied as follows:

SIR, Ralph Giorno argues that theoretical immunology is separate from mathematical immunology and that the argument made in m y article applies to mathematical immunology. I quite agree that the more mathematical the theoretical work becomes, the less likely that work is to be incorporated into general usage by immunologists. I would argue that responsibility for this lies on both sides o f the issue. I believe the ex-

Ordered sequence of expression of class-II antigens and cell-surface immunoglobulin SIR, Keith Guy and Veronica van Heyningen ( Immunol. Today, 1983, Vol. 4, pp. 186-189) reported on the interesting possibility of an ordered sequence of expression of h u m a n major histocompatibility complex ( M H C ) class-II antigens during B-cell maturation. They state that the 'consensus view' holds that during murine B-cell differentiation the expression of surface immunoglobulin (sIg) precedes the expression of class-II antigens in neonatal and adult mice. I hasten to c o m m e n t that m y studies on embryonic mice

perimental immunologist does not choose to spend the time it would take to properly evaluate and use the more mathematically oriented work. I do not agree with Giorno that the mathematically oriented theoretical immunologists 'do very little thorough investigation of the experimental systems they wish to model'. Indeed, one o f the great values of having a theoretical component to any team of researchers is that the theoretician must ask very basic, fundamental

demonstrated that 'Ia appears before Ig as a surface marker of fetal liver cells between days 11 to 16 of gestation' 1. Ia antigens encoded by the murine I-A locus, which are structurally more homologous to h u m a n DC than D R and SB antigens, are present on these embryonic liver cells. A comparative analysis of the temporal pattern of expression of murine I-A and I-E antigens was not performed. Thus, the question of whether an ordered sequence of expression of mouse class-II antigens exists during lymphoid cell development remains unanswered. Nevertheless, the murine studies agree closely with a series o f observations cited by Guy and van H e y n i n g e n which show that 'in h u m a n s some class-II antigen expression precedes sIg expression, since chronic acute lyrnphoblastic leukaemia (cALL) cells are uniformly sIg-negative and

© 1983,ElsevierSciencePubli~ B.V.,Amsterdam 0167- 4919/83/$01.00

questions in order to construct a model. I believe it is incumbent upon the mathematically oriented immunologists to make their work palatable for the experimental immunologists to consume, but the experimentalists must also be open to the contribution this type of work can make. JUDITH RAE LUMB Department of Biology, The Atlanta University, Atlanta, GA 30314, USA.

almost invariably class-II-positive'. These authors also suggest that c A L L cells 'represent one of the earliest recognizable determined stages in the B-cell lineage'. It is intriguing to speculate that the Ia +, s l g - phenotype shared by certain m u r i n e fetal liver cells and h u m a n c A L L cells indicates that these two subpopulations of cells represent a similar, early stage of B-cell differentiation. T h e dialogue between mice and men continues to evolve. T. L. DELOVITCH Banting and Best Department of Medical Research, C. H. Best Institute, University of Toronto, Toronto, Ontario, Canada, M 5 H 1L6.

Reference 1 Delovltch, T. L., Press, J. L. and McDcvitt, H. O. (1978)J. Immunol. 120, 818-824