PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY A N D M E D I C I N E 160.272-277 ( 1979)
Further Investigations of Live Respiratory Syncytial Virus Vaccine Administered Parenteral Iy (40433)
EUGENE B. BUYNAK,* ROBERT E. WEIBEL,** ALFRED J. CARLSON,*** ARLENE A. MCLEAN,* AND MAURICE R. HILLEMAN* *Division of Virus and Cell Biology Research Merck Institute for Therapeutic Research. West Point. Pennsylvania 19486, **Department of Pediatrics, Universily of Pennsylvania, School of Medicine, Philadelphia, PennsJlvunia I9104, and the ***Pediatric Medical Associates, Haverrown. Penn.yvlvaniu I00#3
Respiratory syncytial virus is recognized as tralization test methods and clinical study the single most important viral agent causing procedures for studies 456 and 487 were given serious respiratory disease in infants and in detail previously (16). In the studies, inyoung children (1-5). There is no currently fants and young children residing in suburacceptable vaccine against respiratory syn- ban Philadelphia were each given 0.5 ml of cytial virus infection. Killed virus vaccines vaccine subcutaneously. Older siblings or have not presented evidence of inducing close contacts served as controls. Clinical rehigh-level immunity (6- 10) and live atten- actions were observed for 28 days after vacuated virus vaccines (1 1- 15) given directly cination and blood samples were collected into the respiratory tract have not been sat- immediately prior to and 6 weeks after vacisfactorily developed to date. cination to measure antibody responses and A recent report from this laboratory (16) to detect possible spread of the infection to described the development and clinical test- susceptible contacts. Additional clinical studing of a new live attenuated respiratory syn- ies numbers 508, 509, and 521 were carried cytial virus vaccine that is unlike previously out in the same way in the same open popudeveloped vaccines against the agent in that lations in the Havertown area of suburban it is administered by parenteral injection. It Philadelphia. Modification of the serum neucauses minimal, if any, clinical reactions. The tralization test in the present study consisted vaccine was originally reported to induce ho- of adding sterile guinea pig complement mologous neutralizing antibodies in 75-9396 (Flow Laboratories, Rockville, MD) in a final of initially seronegative persons. Since the concentration of 10% to the virus-human setime of publication, it was found that neu- rum mixtures prior to the one hour incubatralization of respiratory syncytial virus by tion at 37". Results. Potentiation of antibody titers by homologous human antibody is a serum complement-dependent event. When the same added complement. Table I shows the findings sera were reassayed for neutralizing antibody in representative tests of individual sera from in the presence of added complement, nearly nine children who were initially seronegative all initially seronegative persons were shown and who received respiratory syncytial virus vaccine. The examples were selected to repto have developed neutralizing antibody. The present report describes the findings resent the typical findings. Addition of fresh in the previous and in additional clinical trials guinea pig complement increased the neuin which all the sera from the vaccinated tralizing antibody titers of the individual sera persons were assayed in the presence of added from 2- to 32-fold or more showing that the complement. The findings in tests to measure neutralization of respiratory syncytial virus the distribution of neutralizing antibody by human antibody is a complement-dependagainst respiratory syncytial virus in children, ent event. The comparative findings in tests according to age, is also presented. Finally, of postvaccination sera from 78 initially sereported respiratory disease events that oc- ronegative children are shown in Table 11. curred in children during one year after vac- These results show the marked increase in cination are recorded. titer of antibody that occurs when compleMaterials and methods. Preparation of the ment is added. Such increase occurred in all vaccine, viral infectivity titrations, serum neu- but a few sera and the mean fold-increase 272 0037-9727/79/0272-06$0 1 .OO/O Copyright 0 1979 by the Society for Experimental Biology and Medicine All rights reserved. Downloaded from ebm.sagepub.com at GEORGETOWN UNIV MED CTR on September 4, 2015
273
RESPIRATORY SYNCYTIAL VIRUS VACCINE
was approximately fivefold. Neutralizing antibody responses to vaccination in initially seronegative children. Table I11 presents the findings in five clinical studies to measure the neutralizing antibody responses
in 116 initially seronegative children to vaccination with lot 592 or 594 of respiratory syncytial virus vaccine. There were 13 susceptible sibling contact controls. The findings in studies 456 and 487, reported previously (16), presented data using serum neutralization TABLE I. POTENTIATION OF RESPIRATORY SYNCYTIALtests that did not include added complement. NEUTRALIZING ANTIBODYTITER BY GUINEAPIG In these and additional clinical studies in COMPLEMENT OF SERAFROM INDIVIDUAL VACCINATED PERSONSWHO WEREINITIALLY WITHOUTDETECTA- which all sera were tested with added complement, 113 of 1 16 children developed hoBLE ANTIBODY. mologous neutralizing antibody following Neutralizing antibody titer following vaccination vaccination and the mean antibody titers ranged from 1:5 to 1:17. None of the 13 Without With susceptible sibling or close contact controls added added Subject complecompleFolddeveloped antibody. Nasal secretions were No. ment ment difference obtained from a total of eight vaccinated 24 2 4 2 children and tested for homologous neutral1 2 4 8 izing antibody by the method described ear27 4 4 16 lier (16) but with added complement. Table 36 8 4 32 IV shows that only one of four initially sero2 13 16 8 10 2 16 8 negative children showed the presence of an22 16 128 8 tibody in his nasal secretions even though all 3 four children developed circulating antibody. 17 Three of four initially seropositive persons showed an increase in nasal antibody even TABLE 11. COMPARISON OF POSTVACCINATION NEUTRALIZING ANTIBODY TITERSIN TESTSWITH A N D though there was no apparent increase in WITHOUTADDEDCOMPLEMENT AMONG78 CHILDREN circulating antibody in two of the three reWHO WEREWITHOUTANTI BODY^ BEFOREVACCINA- sponders. TION. Neutralizing antibody responses in initially Numbers of postvaccination chilseropositive children given the vaccine. Sera Addidren, according to titer from 52 initially seropositive children two tion of Geomonths to three years of age were selected to com128 metric pleor mean test for neutralizing antibody, in the presence ment titer of added complement, in the sera before and no 5 8 232215 3 1 4 0 after vaccination. The selection was made to 16 1 4 11 10 22 16 8 6 yes achieve as equitable distribution according to a As assayed in the presence of complement. age as was possible. Among the group, 15 ~~~
~_______
TABLE 111. SERUMNEUTRALIZING ANTIBODY RESPONSES IN INITIALLY SERONEGATIVE CHILDREN WHO RECEIVED RESPIRATORY SYNCYTIAL VIRUSVACCINE OR WERECONTACT CONTROLS. Vaccinated persons Vaccine
Non-vaccinated controlsa Response
Study No.
Lot
Passage No.
Age
No. positive/total
Meanb titer
456 508 509 52 I 52 1 487
592 592 592 592 594 594
10 10 10 10 5 5
7 mo-19 mo 6 mo-3 yr 8 mo-21mo 6 mo-20 mo 7 mo-12 mo 9 mo-2 yr
7/7 64/65 6/6 14/16 10/10 12/12
13 17 10 7 5 15
Age
Response No. positive/total
22 mo
o/ 1
2-3 yr
0/5
16 mo-3 yr
0/7
Total group 113/116 (97%) a
Contact controls. Geometric mean titer.
Downloaded from ebm.sagepub.com at GEORGETOWN UNIV MED CTR on September 4, 2015
0/13 (0%)
274
RESPIRATORY SYNCYTIAL VIRUS VACCINE
TABLE IV. CIRCULATING AND NASAL NEUTRALIZINGthat if, indeed, such did occur, ANTIBODY I N CHILDRENO GIVENRESPIRATORY been very mild and clinically SYNCYTIAL VIRUSVACCINE.
it would have inconsequential. Similar results, not reported in detail Neutralizing antibody titers, according to here, were obtained in studies 508, 509, and time of vaccination 521. Circulating Nasal Clinical follow-up in vaccinated persons. Subject Earlier testing by others (8-10) of a killed No. Before Afterb Before Afterb respiratory syncytial virus vaccine suggested 31
Further Investigations of Live Respiratory Syncytial Virus Vaccine Administered Parenteral Iy (40433)
EUGENE B. BUYNAK,* ROBERT E. WEIBEL,** ALFRED J. CARLSON,*** ARLENE A. MCLEAN,* AND MAURICE R. HILLEMAN* *Division of Virus and Cell Biology Research Merck Institute for Therapeutic Research. West Point. Pennsylvania 19486, **Department of Pediatrics, Universily of Pennsylvania, School of Medicine, Philadelphia, PennsJlvunia I9104, and the ***Pediatric Medical Associates, Haverrown. Penn.yvlvaniu I00#3
Respiratory syncytial virus is recognized as tralization test methods and clinical study the single most important viral agent causing procedures for studies 456 and 487 were given serious respiratory disease in infants and in detail previously (16). In the studies, inyoung children (1-5). There is no currently fants and young children residing in suburacceptable vaccine against respiratory syn- ban Philadelphia were each given 0.5 ml of cytial virus infection. Killed virus vaccines vaccine subcutaneously. Older siblings or have not presented evidence of inducing close contacts served as controls. Clinical rehigh-level immunity (6- 10) and live atten- actions were observed for 28 days after vacuated virus vaccines (1 1- 15) given directly cination and blood samples were collected into the respiratory tract have not been sat- immediately prior to and 6 weeks after vacisfactorily developed to date. cination to measure antibody responses and A recent report from this laboratory (16) to detect possible spread of the infection to described the development and clinical test- susceptible contacts. Additional clinical studing of a new live attenuated respiratory syn- ies numbers 508, 509, and 521 were carried cytial virus vaccine that is unlike previously out in the same way in the same open popudeveloped vaccines against the agent in that lations in the Havertown area of suburban it is administered by parenteral injection. It Philadelphia. Modification of the serum neucauses minimal, if any, clinical reactions. The tralization test in the present study consisted vaccine was originally reported to induce ho- of adding sterile guinea pig complement mologous neutralizing antibodies in 75-9396 (Flow Laboratories, Rockville, MD) in a final of initially seronegative persons. Since the concentration of 10% to the virus-human setime of publication, it was found that neu- rum mixtures prior to the one hour incubatralization of respiratory syncytial virus by tion at 37". Results. Potentiation of antibody titers by homologous human antibody is a serum complement-dependent event. When the same added complement. Table I shows the findings sera were reassayed for neutralizing antibody in representative tests of individual sera from in the presence of added complement, nearly nine children who were initially seronegative all initially seronegative persons were shown and who received respiratory syncytial virus vaccine. The examples were selected to repto have developed neutralizing antibody. The present report describes the findings resent the typical findings. Addition of fresh in the previous and in additional clinical trials guinea pig complement increased the neuin which all the sera from the vaccinated tralizing antibody titers of the individual sera persons were assayed in the presence of added from 2- to 32-fold or more showing that the complement. The findings in tests to measure neutralization of respiratory syncytial virus the distribution of neutralizing antibody by human antibody is a complement-dependagainst respiratory syncytial virus in children, ent event. The comparative findings in tests according to age, is also presented. Finally, of postvaccination sera from 78 initially sereported respiratory disease events that oc- ronegative children are shown in Table 11. curred in children during one year after vac- These results show the marked increase in cination are recorded. titer of antibody that occurs when compleMaterials and methods. Preparation of the ment is added. Such increase occurred in all vaccine, viral infectivity titrations, serum neu- but a few sera and the mean fold-increase 272 0037-9727/79/0272-06$0 1 .OO/O Copyright 0 1979 by the Society for Experimental Biology and Medicine All rights reserved. Downloaded from ebm.sagepub.com at GEORGETOWN UNIV MED CTR on September 4, 2015
273
RESPIRATORY SYNCYTIAL VIRUS VACCINE
was approximately fivefold. Neutralizing antibody responses to vaccination in initially seronegative children. Table I11 presents the findings in five clinical studies to measure the neutralizing antibody responses
in 116 initially seronegative children to vaccination with lot 592 or 594 of respiratory syncytial virus vaccine. There were 13 susceptible sibling contact controls. The findings in studies 456 and 487, reported previously (16), presented data using serum neutralization TABLE I. POTENTIATION OF RESPIRATORY SYNCYTIALtests that did not include added complement. NEUTRALIZING ANTIBODYTITER BY GUINEAPIG In these and additional clinical studies in COMPLEMENT OF SERAFROM INDIVIDUAL VACCINATED PERSONSWHO WEREINITIALLY WITHOUTDETECTA- which all sera were tested with added complement, 113 of 1 16 children developed hoBLE ANTIBODY. mologous neutralizing antibody following Neutralizing antibody titer following vaccination vaccination and the mean antibody titers ranged from 1:5 to 1:17. None of the 13 Without With susceptible sibling or close contact controls added added Subject complecompleFolddeveloped antibody. Nasal secretions were No. ment ment difference obtained from a total of eight vaccinated 24 2 4 2 children and tested for homologous neutral1 2 4 8 izing antibody by the method described ear27 4 4 16 lier (16) but with added complement. Table 36 8 4 32 IV shows that only one of four initially sero2 13 16 8 10 2 16 8 negative children showed the presence of an22 16 128 8 tibody in his nasal secretions even though all 3 four children developed circulating antibody. 17 Three of four initially seropositive persons showed an increase in nasal antibody even TABLE 11. COMPARISON OF POSTVACCINATION NEUTRALIZING ANTIBODY TITERSIN TESTSWITH A N D though there was no apparent increase in WITHOUTADDEDCOMPLEMENT AMONG78 CHILDREN circulating antibody in two of the three reWHO WEREWITHOUTANTI BODY^ BEFOREVACCINA- sponders. TION. Neutralizing antibody responses in initially Numbers of postvaccination chilseropositive children given the vaccine. Sera Addidren, according to titer from 52 initially seropositive children two tion of Geomonths to three years of age were selected to com128 metric pleor mean test for neutralizing antibody, in the presence ment titer of added complement, in the sera before and no 5 8 232215 3 1 4 0 after vaccination. The selection was made to 16 1 4 11 10 22 16 8 6 yes achieve as equitable distribution according to a As assayed in the presence of complement. age as was possible. Among the group, 15 ~~~
~_______
TABLE 111. SERUMNEUTRALIZING ANTIBODY RESPONSES IN INITIALLY SERONEGATIVE CHILDREN WHO RECEIVED RESPIRATORY SYNCYTIAL VIRUSVACCINE OR WERECONTACT CONTROLS. Vaccinated persons Vaccine
Non-vaccinated controlsa Response
Study No.
Lot
Passage No.
Age
No. positive/total
Meanb titer
456 508 509 52 I 52 1 487
592 592 592 592 594 594
10 10 10 10 5 5
7 mo-19 mo 6 mo-3 yr 8 mo-21mo 6 mo-20 mo 7 mo-12 mo 9 mo-2 yr
7/7 64/65 6/6 14/16 10/10 12/12
13 17 10 7 5 15
Age
Response No. positive/total
22 mo
o/ 1
2-3 yr
0/5
16 mo-3 yr
0/7
Total group 113/116 (97%) a
Contact controls. Geometric mean titer.
Downloaded from ebm.sagepub.com at GEORGETOWN UNIV MED CTR on September 4, 2015
0/13 (0%)
274
RESPIRATORY SYNCYTIAL VIRUS VACCINE
TABLE IV. CIRCULATING AND NASAL NEUTRALIZINGthat if, indeed, such did occur, ANTIBODY I N CHILDRENO GIVENRESPIRATORY been very mild and clinically SYNCYTIAL VIRUSVACCINE.
it would have inconsequential. Similar results, not reported in detail Neutralizing antibody titers, according to here, were obtained in studies 508, 509, and time of vaccination 521. Circulating Nasal Clinical follow-up in vaccinated persons. Subject Earlier testing by others (8-10) of a killed No. Before Afterb Before Afterb respiratory syncytial virus vaccine suggested 31
