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Development of a vaccine for prevention of congenital cytomegalovirus (CMV) disease is a priority. This study evaluated a "prime-boost" strategy by comparing the safety and immunogenicity of 3 doses of subunit CMV glycoprotein B (gB) vaccine plus MF59 (a squalene-in-water emulsion), 2 doses of a canarypox recombinant vaccine expressing CMVgB (ALVAC-CMVgB) followed by 2 doses of the subunit gB vaccine, 3 doses of both vaccines administered concomitantly, and placebo in 105 healthy, CMV-seronegative adults. Systemic adverse events were rare, but local reactions were common in all groups. After the first subunit vaccination, neutralizing antibody titers in the prime-boost group were comparable to those in subjects receiving 2 subunit vaccinations, indicating a priming effect of ALVAC-CMVgB. However, after the final dose, antibody and cell-mediated immune responses were not significantly different among the groups. All 3 vaccine regimens induced high-titer antibody and lymphoproliferative responses, but no benefit for priming or simultaneous vaccination was detected.

To develop a vaccine against cytomegalovirus (CMV), a canarypox virus (ALVAC) expressing CMV glycoprotein (gB) was evaluated alone or in combination with a live, attenuated CMV vaccine (Towne). Three doses of 106.5 TCID50 of ALVAC-CMV(gB) induced very low neutralizing or ELISA antibodies in most seronegative adults. However, to determine whether ALVAC-CMV(gB) could prime for antibody responses, 20 seronegative adults randomly received either 106.8 TCID50 of ALVAC-CMV(gB) or 106.8 TCID50 of ALVAC-RG, expressing the rabies glycoprotein, administered at 0 and 1 month, with all subjects receiving a dose of 103.5 pfu of the Towne vaccine at 90 days. For subjects primed with ALVAC-CMV(gB), neutralizing titers and ELISA antibodies to CMV(gB) developed sooner, were much higher, and persisted longer than for subjects primed with ALVAC-RG. All vaccines were well tolerated. These results demonstrate that ALVAC-CMV(gB) primes the immune system and suggest a combined-vaccine strategy to induce potentially protective levels of neutralizing antibodies.

Serial serum samples from a 2-year human trial of outer surface protein (Osp) A vaccine were analyzed by Borrelia burgdorferi growth-inhibition assay (GIA) and anti-OspA ELISA to assess the antibody responses of vaccine recipients and subjects with Lyme disease. Although 74% of OspA recipients had a reciprocal GIA titer >/=64 after 3 vaccinations, none of the placebo recipients, even those with Lyme disease, had a GIA titer this high. The correlation between GIA and ELISA titers after 3 doses of vaccine was.84; however, more vaccine recipients had an elevated ELISA titer paired with low GIA titer than had a low ELISA titer with a high GIA titer. OspA-vaccine recipients who acquired Lyme disease had significantly lower serum GIA and ELISA titers after 3 immunizations than did age- and sex-matched OspA recipients without Lyme disease. Thus, vaccinated subjects had antibodies to native antigen on viable cells, and antibody assays with this specificity may predict protection of vaccinees against infection.

Clinical and serum antibody responses following intramuscular injection of two formulations of Salmonella typhi Vi capsular polysaccharide (Vi) were assessed in a double-blind evaluation. Healthy adults were randomly assigned to receive a 25 micrograms dose of liquid (Vi-Liq; n = 182) or freeze-dried Vi vaccine (Vi-Lyoph; n = 55), or placebo (n = 86). Erythema and/or indurationor = 1 cm in diameter at the injection site developed in 13/182 (7%) of Vi-Liq and 3/55 (5%) of Vi-Lyoph recipients (not significant, n.s.). Fever (oral temperatureor = 100 degrees F (37.8 degrees C)) occurred in2% of vaccinees. The frequencies of rises of fourfold or greater and of maximal Vi antibody levels were similar in the two vaccine groups. Fourfold or greater rises in serum Vi antibody levels (RIA) developed in 53% of Vi-Lyoph and 60% of Vi-Liq recipients by 1 week (n.s.), and 98 and 93%, respectively, by 1 month (n.s.). The frequencies of adverse reactions and mean Vi antibody levels following booster immunization with Vi-Liq 27 to 34 months after primary immunization (n = 55) were similar to those observed following primary immunization, although subjects given a booster dose were more likely to develop local reactionsor = 1 cm in diameter than those given a first dose (10/55 versus 13/182, p = 0.013 by the chi 2 test). Primary and booster immunizations with the Vi vaccines are well tolerated in healthy adults; mean Vi antibody levels remain significantly elevated for up to 34 months after primary immunization.

We immunized 24 patients (mean age 15.2 +/- 9.3 months) with polyribosylribitol phosphate-diphtheria toxoid conjugate vaccine (PRP-D) 2 months after a systemic Haemophilus influenzae type b infection. Children less than 24 months of age were immunized twice. Serum was obtained for antibody to PRP before and 1 or 2 months after immunization. Three of five children greater than 24 months of age and three of six children 18 to 24 months of age developed greater than 1 microgram/ml of antibody after immunization, and geometric mean postimmunization levels were significantly greater than preimmunization levels for both groups. However, two children who failed to respond to conventional PRP vaccine did not respond as expected to one dose of PRP-D. For children 7 to 17 months of age, the geometric mean PRP antibody levels increased as follows: preimmunization, 0.05 micrograms/ml; after the first dose, 0.28 micrograms/ml (p = 0.003); and after the second dose, 3.39 micrograms/ml (p = 0.001). Of 13 children, 10 developed antibody values greater than 1.0 micrograms/ml. PRP conjugate vaccines are immunogenic in young children who have not developed protective PRP antibody levels after a systemic H. Influenzae type b infection.

Forty healthy adult males were given a 20-micrograms intramuscular dose of either a new recombinant hepatitis B virus (HBV) vaccine produced in mammalian cells (rHBsAg) or the currently licensed HBV vaccine derived from human plasma (HEPTAVAX-B), and booster doses were administered one month and six months later. The percentage of vaccinees who seroconverted on the 10th and 30th days after the first vaccination was higher for the rHBsAg vaccinees than for the recipients of plasma-derived vaccine (rHBsAg: 10% on day 10 and 70% on day 30; HEPTAVAX-B: 0% and 25%, respectively). The only statistically significant difference in titers of antibody to HBV surface antigen was noted 30 days after the first vaccination. Both vaccines induced a shift in antibody from the 19S to the 7S fraction and a specific antibody response to the a determinant. The rHBsAg vaccine was not associated with significant reactogenicity or toxicity and was somewhat more immunogenic than the currently licensed product.

Naturally acquired humoral immunity is thought to protect adults against serious infections due to Haemophilus influenzae type b (Hib). Antibody to the polyribosylribitol phosphate (PRP) capsule is generally considered protective; antibody to lipooligosaccharide (LOS) or outer membrane protein (OMP) may also play a role. Serum from 23 of 50 healthy young adults had no bactericidal effect (BE) against Hib yet opsonized these organisms for approximately 30% uptake by polymorphonuclear leukocytes. The degree of bactericidal and opsonizing activity in serum from the other 27 subjects generally correlated with the level of antibody to PRP but not to LOS or OMP. However, serum from some individuals had levels of antibody to PRP as high as 4.9 micrograms/ml without BE, and seven of 27 subjects with BE had antibody levels of less than 1 microgram/ml. After vaccination with 20 micrograms of conjugated PRP, the level of antibody to PRP was greater than 5 micrograms/ml in all 50 subjects. BE appeared in 22 of those who originally lacked it, and opsonization increased to approximately 50%.

Clinical and serologic responses to inactivated influenza virus vaccines were studied in 444 children in Los Angeles under doubld-blind, placebo-controlled protocols. One- and two-dose regimens employing monovalent (A/New Jersey/76) and bivalent (A/New Jersey/76-A/Victoria/75) vaccine were studied in separate trials. In a single dose, whole-virus vaccines were more potent than split-product vaccines as primary inducers of immunity against influenza A/New Jersey/76 virus. Split-product vaccines were better tolerated clinically and, after two-dose regiments, produced rates of seroconversion (greater than 90%) against A/New Jersey/76 virus comparable to those produced by two doses of whole-virus vaccines. Analysis of heterotypic antibody responses induced by monovalent A/New Jersey/76 vaccines revealed only slight increases in antibody against influenza A/Victoria/75 virus. After vaccination with bivalent vaccines, levels of antibody against influenza A/Victoria/75 virus were significantly higher in subjects who received high doses of split-product vaccines than in subjects who received whole-virus vaccines.

A 16 μg dose of HBsAg prepared by the National Institute of Allergy and Infectious Diseases was administered to 71 children, 18 months to 16 years old. The frequency of seroconversion reached 59% (range: 50–78%) at two weeks following the first dose of vaccine and approached 100% one month after the second dose. There were virtually no side effects. Children less than three years of age developed significantly greater anti-HBs responses than did older children or adults. This appears to be related to the greater dose in μg kg −1 administered to these children. Anti-HBs responses (mIU ml −1 ) to the vaccine by the Oriental participants were lower at each sampling interval. Our data suggest that prolonging the third dose of vaccine past six months (e.g. to 12 months) may not significantly alter the eventual antibody levels attained by the vaccinees, but may result in suboptimal protection between the second and third dose in some of them.

A group B Neisseria meningitidis serotype protein vaccine was studied clinically in adults. The vaccine comprised lipopolysaccharide-depleted outer membrane vesicles from a serotype 2b strain, 3006-M2, noncovalently complexed with group B meningococcal polysaccharide. Volunteers received 25 micrograms each of protein and polysaccharide administered intramuscularly either in 0.9% NaCl or adsorbed onto aluminum hydroxide on weeks 0 and 6. Most individuals experienced mild local reactions, but there were no systemic reactions. Both vaccine formulations stimulated antibodies to the outer membrane proteins of serotypes 2a:P1.2 and 2b:P1.2, but higher levels were achieved with the aluminum hydroxide-adsorbed vaccine after two immunizations. Vaccine-induced antibodies were primarily IgG and were bactericidal for both a serotype 2a and a serotype 2b strain. Induction of bactericidal antibodies has been shown to be a major predictor of protection against meningococcal disease.

During a measles immunization campaign 203 children were enrolled in an antibody response study. Of this group, follow-up clinical data and sera samples were available from 125 children three weeks after immunization and from 90 children ten months later. Seventy-six of the children had been previously vaccinated, ten had a history of measles and 39 denied vaccination or illness. Twenty-six of the children had prevaccination hemagglutination inhibiting antibody titers of less than 5. Of this group 12 had a primary immune response (IgM measles antibody) with geometric mean titers (GMT) of 90 and 40 three weeks and ten months respectively after vaccination. In contrast, the other 14 children with initial titers of less than 5 had secondary immune responses (only IgG measles antibody) with GMTs of 28 and 9 three weeks and ten months after vaccination. Since the antibody responses in these children who had previously been stimulated by measles antigen were modest and transient, it is suggested that booster immunization may not be effective in preventing future secondary vaccine failures. Also noted in this study was a poor correlation between historical data and actual measles antibody.

One hundred adult volunteers were administered inactivated vaccine (20 micrograms/0.5 cc) intramuscularly (IM) or intranasally (IN), or 10(4.7) TCID50 of a live cold-adapted vaccine (CR35) IN. Microneutralization (Nt) and radioimmunoprecipitation methods were employed to measure hemagglutinin antibody responses in sera, nasal washes, and in bronchopulmonary lavage fluids. In unprimed recipients, the relative frequency of serum antibody response and magnitude of rise was highest following the IM-inactivated vaccine (100%) and lowest after IN-live vaccine (29%). However, in individuals with pre-existing antibody, the three vaccines given were comparably immunogenic. Occurrences of secretory IgA hemagglutinin antibody in nasal washings were more frequently associated with topical administration of live or inactivated vaccine, whereas, IgG hemagglutinin antibody responses occurred with equal frequency in nasal washings in all three vaccine groups. Analysis of the hemagglutinin antibody responses in the lower respiratory tract showed that the IN-live vaccine favored the induction of secretory IgA hemagglutinin antibody and the IM-inactivated vaccine stimulated a more frequent IgG hemagglutinin antibody response.

Bactericidal and enzyme-linked immunosorbent assays were used to determine the immunoglobulin classes responsible for group- and type-specific immunity to Neisseria meningitidis among healthy, unvaccinated individuals and persons who received group-B N meningitidis polysaccharide-serotype-2 protein vaccine. Bactericidal antibodies to the group B polysaccharide were primarily IgM; only a few individuals had both IgM and IgG antibodies. IgG bactericidal antibodies were detected only in those individuals with high IgM-antibody levels to group B meningococci. Increased levels of bactericidal antibodies to the group-B polysaccharide were infrequently found in vaccinees, possibly because of high prevaccination bactericidal-antibody levels. Bactericidal antibodies to the group-C polysaccharide were IgM, IgG, or both. Vaccine-induced antibodies to lipopolysaccharide were not bactericidal for a group-C serotype-2 strain with the lipopolysaccharide immunotype of the vaccine strain.

Safety and immunogenicity of a Haemophilus influenzae type b polysaccharide-diphtheria toxoid conjugate vaccine (PRP-D) was evaluated in infants seven to 14 months of age. PRP-D (80% of subjects) or saline placebo (20%) was randomly and blindly administered (two doses separated by two months). Incidence of mild reactions lasting less than 48 hr did not differ significantly between the placebo and vaccine recipients. Preimmunization levels of antibody to PRP were less than or equal to 0.15 micrograms/ml in 97% of subjects. A twofold increase in antibody concentration occurred in 88% of subjects following the first dose and in 99% following the second dose of vaccine. No change occurred in placebo recipients. Mean level of antibody and percentage of subjects with levels of antibody greater than or equal to 1 microgram/ml after vaccination increased with increasing age. Responses were related to vaccine lot but not to sex, race, or geographic location. Two doses of PRP-D in infants seven months of age and older induced antibody levels equal to or greater than levels in infants 24 months of age given the polysaccharide alone.

The efficacy of PRP-D vaccine in young infants has been documented in previous studies. We now report the response of patients with IgG subclass deficiency (GSD) to a single immunization with PRP-D. Patients with GSD ranging in age from 6 to 10 years were given a single i.m. dose of 20 μg PRP-D. Total serum anti-PRP antibody levels were determined using a modified Farr assay and radiolabeled PRP. Four patients with GSD and no major abnormalities in B- and T-cell subsets or in vitro mitogen stimulation had a mean preimmunization anti-PRP level of 1.61 μg/ml which rose to 22.6 μg/ml 3-4 weeks after immunization. The mean increase in anti-PRP for 3 patients with IgG2 deficiency was 18.8 μg/ml. Two patients with IgA and IgG2 deficiency responded with post-immunization anti-PRP levels of 10.8 and 40 μg/ml. Both of these patients failed to respond to immunization with a polyvalent pneumococcal polysaccharide (PS) vaccine. One patient with isolated IgG3 deficiency responded normally to diphtheria and tetanus toxoid, to 3 of 4 pneumococcal serotypes tested, and had a rise of anti-PRP antibody from 0.6 to 28.4 μg/ml. A fifth patient with common variable immunodeficiency had no response to immunization with any of the above vaccines. These data suggest that protein conjugate vaccines may lead to effective immunization of patients with defective PS antigen processing.

During a measles immunization campaign blood samples were collected from 203 children before vaccination. Follow up specimens were collected from 125 children 3 wks. later and from 88 children 10 mos. later. Of the 125 children with follow up study, 88 had been previously vaccinatedt 10 had a history of measles and 27 denied vaccination or illness. Measles HAT antibody geometric mean liters (GMTs) were 13, (day 0), 38 (3 wks.), and 23 (10 mos.). Twenty-six of the 125 had HAI liters of – 5 prior to vaccination and showed a ≥4-fold antibody titer rise. IgM measles antibody was detected in 12 of these children after protein-A and 2-ME treatment with a GMT at 3 weeks and 10 months of 61 and 40 respectively. There was no history of measles exposure or vaccination in this group. In the remaining 14 children with initial titers < 5 no IgM antibody response was detected, and despite a 4-fold increase in HAI titer at 3 wks. (GMT 28), the 10 month titer had dropped considerably (GMT 9). Ten of these 14 children had a history of previous measles vaccination. The remaining 99 children had detectable initial titers between 5 and 320. After grouping these according to their pre-booster titers, no significant change in GMTs was observed when day 0, 3 wk. and 10 mo. results were compared. Our study suggests that HAI antibody titers in children previously immunologically stimulated against measles are not altered significantly by revaccination, even when the pre-booster titers are low or not detectable.

In a multicenter study, 502 normal infants ages 7-14 months were randomized to receive either 2 doses of PRP-D intramuscularly containing 20 ug PRP (80%) or placebo (20%) 6-10 weeks apart. Serum samples were obtained from 25% prior to each injection and 1 month post second dose and tested by Farr-type radioimmunoassay for anti-PRP antibody. Reaction data are available from 400 subjects. The incidence of local erythema at the injection site was 2.4% and irritability 3% in both groups. Two PRP-D recipients had temperatures greater than 1022(R). Among 120 children tested for antibody, 99% of PRP-D recipients demonstrated a two fold or greater rise in anti-PRP compared with 5% of placebo recipients. Median anti-PRP levels in the two groups were 7.0 and 0.012 ug/ml respectively. After 2 doses of PRP-D, 95% had ≥ 0.15 ug/ml antibody protein/ml and 90% had > 1 ug/ml. This study confirms prior observations in 9-14 month olds that PRP-D can induce primary and booster antibody responses in infants over 7 months compatible with protection against H. influenzae b disease.

PRP vaccine is a poor immunogen when administered to some children following Hib infection or their sibs. To date, we have immunized 18 patients (mean age 19 mos., range 7-45 mos; 14 meningitis) with PRP-diphtheria toxoid conjugate vaccine (PRP-D) containing 20 μg PRP. Children were inoculated 1-8 mos. (15 ≤ 2 mos.) post illness with 1 or 2 doses of PRP-D. Serum was obtained for anti-PRP Ab (radioantigen binding assay at Connaught Laboratories) prior to and 1 month post vaccine. Serology is available on 13 patients, 6 of whom were Ab negative ( < 0.012 μg/ml) pre-vac (4 were ≤ 16 mos. when immunized). Anti-PRP rises developed in 11/13 patients and 5/6 pre-vac Ab negative patients. The pre- and post-geometric mean titers were 0.13 and 2.0 μg/ml, respectively (p < 0.001 for log transformed data). One patient (pre-vac Ab neg), a non-responder to routine PRP given at 24 mos., developed 0.28 ug/ml anti-PRP Ab following PRP-D at 26 mos. Anti-PRP Ab developed in 3/3 sibs, (8, 11, and 24 mos.), 2 of whom were Ab negative pre-vac. Our data indicate that young children who may not have developed anti-PRP within 1 or 2 mos. of Hib infection usually respond to 1 or more doses of PRP-D and suggest that children at increased risk for Hib disease will likely respond to PRP conjugate vaccines.

AUGMENTED ANTIBODY (Ab) RESPONSES IN INFANTS ADMINISTERED A NEW HAEMOPHILUS INFLUENZAE TYPE B CAPSULAR POLYSACCHARIDE (PRP) DIPHTHERIA TOXOID CONJUGATE VACCINE (PRP-D)