Biomedical subjects
Publications and source records attributed to R G Brackett.
Specific immune serum was found to inhibit the dispersal of the merozoites from mature schizonts, thus interfering with their subsequent reinvasion of new host erythrocytes. This phenomenon is viewed as a protective mechanism against malaria which can be measured in vitro and reflects the immune status of the donor.
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Influenza infection in renal transplant recipients may cause either morbidity and mortality or acute allograft rejection; thus, routine annual influenza vaccination should be considered. We have studied the humoral and cellular immune responses to influenza virus antigens before and after trivalent vaccine administration in 13 patients and 16 control subjects. The patients, nine of whom were either on alternate-day or low-dose daily steroid therapy, showed highly significant serum hemagglutination-inhibition antibody responses to each influenza virus strain, There was no significant change in mean lymphocyte stimulation index to any influenza virus strain after vaccination in either group. There was no correlation in the patient group between hemagglutination-inhibition antibody titer or response, or lymphocyte stimulation index or response, and the degree of allograft function or dose or duration of immunosuppressive therapy. The vigorous antibody response and the evidence of cellular immunity support the efficacy of influenza vaccination in these patients.
A system with continuous flow of medium that uses disposable tissue culture flasks for the in vitro cultivation of P. falciparum is described. This scaled-up modification of the Trager and Jensen method gives merozoite yields sufficient for experimental vaccine studies in animals. A method of increasing the yield of merozoites by decreasing the pH of the medium is presented.
Two bivalent, ether-treated, subunit influenza vaccines were compared in adults greater than or equal to 45 years old. Both vaccines contained 200 chick cell-agglutinating (CCA) units of A/Victoria/3/75 antigen/dose. The Hsw1N1 components, also at a level of 200 CCA units/dose and designated A/Shope and A/X-53, were antigenically representative of the A/swine/1976/31 and A/New Jersey/8/76 viruses, respectively. A/Shope virus possessed about 100 times more neuraminidase activity than A/X-53 virus. The two vaccine groups had equivalent geometric mean titers (GMTs) of antibody to A/NJ virus, with about 95% of each group having titers of greater than or equal to 1:40 after vaccination. Group GMTs of antibody to A/Vic virus were also equivalent. Failure of the A/X-53 vaccinees to respond according to the dogma of original antigenic sin and a highly significant between-group difference in response to A/PR/8/34 antigen are interpreted as due to a difference in vaccine neuraminidase levels. It is suggested that, although A/Shope was as serologically effective against A/NJ virus as A/X-53 in this age group, under similar conditions a recombinant with the A/NJ hemagglutinin and the stable A/swine neuraminidase antigens might be more effective against A/NJ than either of the present vaccines.
Reactivity and immunogenicity of three inactivated, zonally purified, monovalent influenza A/swine virus vaccines were studied in children and adults. Each dose of vaccine contained either 400 chick cell-agglutinating (CCA) units/0.5 ml or 200 CCA units/0.25 ml. The vaccines contained either whole virus or ether-extracted, subunit virus with or without 1.5 mg of A1PO4/0.5 ml. Children younger than 10 years of age received a half dose. Substantial system reactions, including temperature increases of 2.2 F-4.9 F, were observed in all children who received whole-virus vaccines. In contrast, ether-extracted, subunit vaccines (with or without A1PO4) were minimally pyrogenic in 185 subjects. Two doses of subunit vaccine in subjects younger than 25 years of age were immunologically equivalent to a single dose in older subjects. We concluded that two doses of ether-extracted, subunit virus vaccine with Hsw1N1 antigen, administered at least four weeks apart, are serologically effective for immunization of seronegative subjects of any age and that this dosage regimen should be used in young children in whom whole-virus vaccines are unacceptably reactive.
Reactivity and immunogenicity of two inactivated, zonally purified, ether-extracted, influenza A/New Jersey/X-53 subunit virus vaccines were studied in 103 children three to 18 years of age. Children aged nine years of younger received doses of 100 or 200 chick cell-agglutinating (CCA) units, and those older than nine years received doses of 200 or 400 CCA units. Vaccines were given intramuscularly. Two doses were given at intervals of four weeks. The vaccines were minimally pyrogenic, causing only two instances of temperatures of greater than 100.0 F. Other systemic reactions were observed infrequently. Tenderness at the site of injection occurred relatively frequently but was of no medical consequence. The geometric mean titers of homologous antibody, which ranged from 1:52 to 1:75 after administration of two doses, were statistically equivalent in all treatment groups. Titers of antibody of greater than or equal to 1:40 to the influenza A/New Jersey/8/76 virus strain were achieved by 88% of the vaccinees. We concluded that two doses of ether-extracted, subunit influenza A/New Jersey/X-53 virus vaccine were well tolerated and, when given at least four weeks apart, were serologically effective for immunization of children aged three to 18 years.
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Specific rubella antibody detectable by indirect immunofluorescence developed in response to immunization with attenuated rubella vaccine, HPV-77, DK-12. Fluorescent antibody (FA) was found when vaccinee sera were reacted with antigens synthesized in three different acutely infected continuous cell lines: BHK-21, LLCMK-2, and RK-13. FA titers were high, and they correlated with antibody titers obtained by hemagglutination-inhibition tests. Levels of FA in vaccinated individuals were slightly lower than those found in persons recovered from natural rubella infections. Rubella FA persists a long time in convalescent individuals and appears to be maintained for at least 19 months in vaccinees.
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