Age-associated differences in immunoglobulin G1 (IgG1) and IgG2 subclass antibodies to pneumococcal polysaccharides following vaccination.

Immunoglobulin G (IgG) subclass antibody responses to pneumococcal vaccines were determined for human subjects in four age groups. The ratios of IgG1/IgG2 antibody concentrations declined with advancing age for all five of the serotypes tested. Protein-conjugate vaccines elicited enhanced IgG antibody responses over plain polysaccharide vaccines in infants but not in adult groups.

Oligoclonality of serum immunoglobulin G antibody responses to Streptococcus pneumoniae capsular polysaccharide serotypes 6B, 14, and 23F.

Serum antibodies (Abs) specific for the capsular polysaccharides of Streptococcus pneumoniae provide protection against invasive pneumococcal disease. Previous studies indicate that Abs to pneumococcal polysaccharide (PPS) serotypes 1 and 6B have limited clonal diversity. To determine if restricted diversity was a feature common to other PPS specificities, we examined the light (L)-chain expression and isoelectric heterogeneity of type 6B, 14, and 23F Abs elicited in 15 adults following PPS vaccination. At the population level, both PPS-6B and PPS-14 Abs expressed kappa and lambda chains, although 6B Abs more frequently expressed lambda chains lambda and 14 Abs more frequently expressed kappa chains. In individual sera, Abs were generally skewed towards either kappa or lambda expression. 23F-specific Abs had predominantly kappa chains. Isoelectric focusing analyses showed that sera contained one or at most a few immunoglobulin G Ab spectrotypes to all three respective capsular serotypes, a result indicative of oligoclonality. A sequence analysis of a purified PPS-14-specific Ab having a single spectrotype gave uniform amino-terminal sequences for both the heavy chain (V(H)III subgroup) and the L chain (kappaIII-A27 V region). From these results we conclude that within individual adults, serum Ab responses to PPS serotypes 6B, 14, and 23F derive from a small number of dominant B-cell clones, and consequently variable-region expression is probably individually limited as well. Oligoclonality appears to be a general characteristic of human PPS-specific Ab repertoires, and we suggest that this property could lead to individual differences in Ab fine specificity and/or functional activity against encapsulated pneumococci.

Influenza virus vaccination of patients with chronic lung disease.

STUDY OBJECTIVES: To evaluate the safety of, and mucosal and systemic immune responses induced by two influenza virus vaccine regimens in subjects with COPD. DESIGN: Single-center, blinded, randomized, prospective clinical trial evaluating two vaccine regimens. SETTING: Outpatient clinics of St. Louis Department of Veterans Affairs Medical Center. PARTICIPANTS: Volunteers (age range, 42 to 88 years) had preexisting COPD with severe obstruction to airflow on average, were male, and were not receiving immunosuppressive medication. INTERVENTIONS: Twenty-nine volunteers were randomly assigned to receive either bivalent live attenuated influenza A virus vaccine (CAV) or saline solution placebo intranasally. All subjects also received an i.m. injection of trivalent inactivated influenza virus vaccine (TVV) simultaneously. MEASUREMENTS AND RESULTS: Clinical status and pulmonary function measured by spirometry did not change significantly after vaccination. Using hemagglutinins (H1 and H3 HA) which more closely resembled those in CAV, mean levels of anti-HA immunoglobulin A (IgA) antibodies in nasal washings increased significantly after vaccination with CAV and TVV compared to prevaccination, but they did not increase significantly after TVV and intranasal placebo. Mean levels of influenza A virus-stimulated interleukin-2 and -4 produced by peripheral blood mononuclear cells in vitro increased significantly after administration of the combination vaccine regimen and to a lesser extent after TVV and intranasal placebo compared to respective prevaccination levels. The timing of the cytokine response appeared different following CAV and TVV compared to TVV and intranasal placebo. CONCLUSIONS: Intranasally administered CAV was safe when given with i.m. administered TVV and there may be an immunologic advantage to administration of the combination vaccine regimen compared to TVV with intranasal placebo.

Humoral and cellular immune responses following vaccination with purified recombinant hemagglutinin from influenza A (H3N2) virus.

Adults were immunized with either baculovirus-expressed, purified recombinant hemagglutinin (rHA) from influenza A/Beijing/32/92 (H3N2) virus or saline placebo and evaluated for humoral and in vitro cellular immune responses. Compared with responses in placebo recipients, vaccinees had greater postvaccination H3(Beijing/32) HA (H3)-specific lymphoproliferation and interleukin (IL)-2, IL-10, and interferon-gamma (IFN-gamma) production. Mean increases in the production of IL-10 (> or = 20-fold) and IL-2 (10-fold) were relatively greater than that of IFN-gamma (4-fold) or IL-4 (no change). Serum H3 antibodies were induced in 80% of rHA recipients, and the rise in antibody titer was significantly correlated with changes in IL-2, IL-10, and IFN-gamma concentrations. Vaccination with rHA only minimally enhanced anti-influenza virus cytotoxic T lymphocyte activity. These data demonstrate that rHA immunization of adults elicits a significant recall response by memory B and T lymphocytes and suggest that the cytokine response to vaccination has a T helper cell type 0-like profile.

Summary of a clinical trial with liposome-adjuvanted influenza A virus vaccine in elderly adults.

In a randomized, double-blinded study, 77 elderly seropositive volunteers were immunized with either liposome-adjuvanted or control subvirion vaccine containing 15 micrograms/dose of haemagglutinin from influenza A/Taiwan/1/86 (H1N1) virus. The liposome vaccine was well-tolerated but elicited serologic responses that were no different in frequency or magnitude from those induced by the control vaccine. Less than 20% of subjects in either group mounted a 4-fold or greater rise in antibody titer. Peripheral blood anti-influenza A cytotoxic T lymphocyte activity was enhanced to a greater extent by the liposome vaccine than by the control subvirion vaccine. It remains unclear whether liposome-adjuvanted formulations would have an advantage over conventional influenza vaccines for routine annual reimmunization of targeted high-risk populations.

Neuraminidase-specific antibody responses to inactivated influenza virus vaccine in young and elderly adults.

Little information is available on the potential role of antibody to influenza virus neuraminidase (NA) in vaccine-induced immunity. In the present study, serologic responses to the N1Texas/91 and N2Beijing/92 NA components of trivalent inactivated influenza virus vaccine were measured by NA inhibition (NI) and enzyme-linked immunosorbent assay (ELISA), and the results for adults aged 18 to 45 (young) or > or = 65 (elderly) years were compared. The two age groups had comparable rates (32 to 50%) of NI response. In contrast, ELISA immunoglobulin G (IgG) antibody responses to N1 and N2 NAs occurred in 70 to 71 and 67 to 83%, respectively, of young subjects but in only 3 to 18 and 18 to 35%, respectively, of elderly subjects. prevaccination mean ELISA IgG and IgA NA antibody titers were generally lower for the young adults than they were for the elderly, whereas the corresponding NI titers were comparable. In young adults, plaque size-reducing NA antibody increases were positively associated with ELISA but not with NI antibody increases. There were no apparent age-related differences in the immunoglobulin isotype distribution of the anti-NA response, with IgG being the dominant class and IgG1 the dominant subclass of serum antibody. Anti-hemagglutinin antibody responses to H1Texas/91 and H3Beijing/92 were greater in magnitude and frequency than the corresponding NA-specific responses to N1Texas/91 and N2Beijing/92 when measured by hemagglutination inhibition and NI, respectively, but not when measured by ELISA. The discordance between NI and ELISA for measurement of NA-specific vaccine responses may reflect the relative insensitivity of NI in discriminating differences when initial antibody titers are low.

Hepatitis B virus vaccination for older adults.

OBJECTIVE: To compare in adults more than 50 years old the tolerability and immunogenicity of vaccination with recombinant hepatitis B surface antigen (HBs) compared with vaccination with recombinant hepatitis B protein PreS2 + S, and to investigate the safety and immunogenicity of a fourth vaccine dose in poor and non-responders. DESIGN: Randomized, double-blind prospective study. SETTING: General clinical research center for outpatient evaluation and vaccination. SUBJECTS: Adults older than age 50 who were in general good health and with no known risk factors for acquiring or serologic evidence of hepatitis B virus infection. INTERVENTION: Subjects were randomized to receive 10 mcg HBs (Recombivax, Merck, Sharp and Dohme), 12 mcg PreS2 + S, or 24 mcg PreS2 + S vaccine at 0, 1, and 6 months. Poor and non-responders (anti-Hbs < 10 mIU/mL at month 9 and/or 12) were encouraged to receive a fourth vaccine injection. MEASUREMENTS: Diary records of temperature and local and systemic reactions following each vaccination were maintained by all subjects. Anti-HBs levels were measured by radioimmunoassay before the first injection, at 1, 2, 3, 6, 7, 9, and 12 months after for all subjects, and 1 month after the fourth injection for the group of poor and non-responders. MAIN RESULTS: Twenty men and nine women (mean age +/- SD, 66 +/- 8.0 years) were enrolled. Ten subjects received HBs vaccine, nine received 12 mcg PreS2 + S vaccine, and 10 received 24 mcg PreS2 + S vaccine. One subject in the HBs group dropped out, and data were analyzed for the remaining 28 subjects. There were no differences in rates of side effects reported by each of the three groups. Overall, minor local adverse reactions occurred in 12 (40%) after at least one of the first three vaccinations. Systemic side effects occurred in five (17%) after the first vaccination, in one after the second, but in none after the third. The 24-mcg PreS2 + S vaccine was not more immunogenic than the HBs vaccine, and the 12-mcg PreS2 + S vaccine was judged inadequate. Nineteen of 22 (86%) poor and non-responders received a fourth vaccination. Minor local adverse reactions were reported by six (32%), and none reported a systemic side effect. For the 12 subjects receiving a fourth injection of HBs or 24 mcg PreS2 + S vaccine, the proportion of responders 1 month following the fourth injection was greater than for 1 month following the third injection (11 of 12 [92%] versus 12 of 19 [63%], respectively, P < .05). CONCLUSION: For adults more than 50 years of age who have low anti-HBs levels after three vaccine injections, a fourth injection is well tolerated and results in improved immunogenic response.

Evaluation of a recombinant hemagglutinin expressed in insect cells as an influenza vaccine in young and elderly adults.

Healthy subjects <45 years old (young adults) or >65 (elderly adults) were randomized in double-blind fashion to receive intramuscularly subvirion trivalent influenza vaccine, placebo, or 15, 45, or 135 microgram of the hemagglutinin (HA) of the influenza A/Beijing/32/92 (H3N2) virus expressed in insect cells by a recombinant baculovirus (rHA0). All vaccines were well tolerated. Both young and elderly adults manifested serum hemagglutination-inhibition, virus neutralizing, and HA-specific IgG ELISA antibody responses to rHA0 vaccine. In young adults given 135 microgram of rHA0, the vaccine was significantly more immunogenic than subvirion influenza vaccine. Elderly adults also had increased antibody responses to 135 microgram of rHA0 compared with subvirion vaccine, but the difference was not statistically significant. These results demonstrate that high-dose rHA0 vaccines are well tolerated and effectively induce both functional and binding serum HA-specific antibody in young and elderly adults.

Reactogenicity and immunogenicity of a protein-conjugated pneumococcal oligosaccharide vaccine in older adults.

Healthy adults > or = 50 years old were immunized with either pentavalent Corynebacterium diphtheriae C7 (beta197) cross-reactive material (CRM197) protein-conjugated pneumococcal vaccine (CV) containing 10 microgram each of capsular oligosaccharides from serotypes 6B, 14, 18C, 19F, and 23F or with licensed (23-valent, 25 microgram/serotype) pneumococcal polysaccharide vaccine (PV). Adverse reactions, predominantly local in nature, occurred in 20 of 23 CV recipients versus 13 of 23 PV recipients (P<.05). Compared with mean postvaccination antibody concentrations in PV recipients, those induced by CV were not significantly different for serotypes 6B, 14, 18C, and 23F and were lower for 19F (P<.05). Six months later, reimmunization with PV of subjects who had initially received CV elicited a slight boost in antibody concentrations to levels that were not significantly higher than those achieved after the primary vaccination or than those in persons given a single dose of PV. Pneumococcal vaccines containing protein-conjugated oligosaccharides may offer no advantage over currently licensed preparations containing unconjugated polysaccharides for immunization of healthy older adults.

Induction of mucosal antibodies by live attenuated and inactivated influenza virus vaccines in the chronically ill elderly.

Induction of local antibody responses to influenza A virus hemagglutinin by coadministration of two vaccines was investigated. Fifty elderly nursing home residents received inactivated trivalent influenza virus vaccine intramuscularly and simultaneously were randomized to receive either bivalent live attenuated influenza A virus vaccine or saline placebo intranasally in a blinded fashion. More significant increases in anti-H1 and -H3 IgA antibodies were detectable in nasal wash specimens of subjects who received live attenuated virus vaccine than in those who received intranasal placebo. The increased anti-hemagglutinin IgA antibody response was of longer duration in recipients of live attenuated vaccine. The change in antibody titers after vaccination was positively correlated with total blood lymphocyte counts measured before vaccination in both vaccinee groups (P < .05). There was a possible advantage of administering live attenuated with inactivated virus vaccines because of enhanced local antibody responses.

In previously immunized elderly adults inactivated influenza A (H1N1) virus vaccines induce poor antibody responses that are not enhanced by liposome adjuvant.

In a randomized, double-blinded study, 77 healthy elderly seropositive volunteers (95% of whom had received influenza vaccine within the prior 5 years) were immunized with either monovalent liposome-adjuvanted or control subvirion vaccine containing inactivated influenza A/Taiwan/1/86 (H1N1) virus. The experimental vaccine was well-tolerated but elicited serologic responses that were no different in frequency or magnitude from those induced by the control vaccine. Less than 20% of subjects in either group mounted a fourfold or greater rise in antibody titer. Sixty-three elderly subjects who had participated in the liposome vaccine trial were reimmunized 18 weeks later with licensed trivalent subvirion vaccine, and their serologic responses were compared with those of 26 young adults. Significant rises in hemagglutination inhibition (HAI) antibody titers to the A/Texas/36/91 (H1N1), A/Beijing/32/92 (H3N2) and B/Panama/45/90 components occurred in 10%, 76% and 56% of elderly vaccinees, respectively, compared to 92% (p < 0.0001), 100% (p < 0.005) and 88% (p < 0.005) of young vaccines, respectively. Age differences in seroresponse rates to the H1N1 subtype antigen were significant even when comparing young and old adults with identical prevaccination HAI antibody titers. These data confirm prior observations suggesting that previously immunized elderly persons have impaired serologic responses to influenza vaccines, particularly against recently circulating H1N1 subtype antigens. It remains unclear whether liposome-adjuvanted formulations would have an advantage over conventional influenza vaccines for routine annual reimmunization of targeted populations.

Cytotoxic T lymphocyte responses to a liposome-adjuvanted influenza A virus vaccine in the elderly.

This randomized double-blind study evaluated cytotoxic T lymphocyte (CTL) responses of elderly volunteers after parenteral immunization with either liposome-adjuvanted (n = 23) or control subvirion (n = 26) vaccine containing detergent-split influenza A/Taiwan/1/86 (H1N1) virus. Peripheral blood mononuclear cells obtained 0, 2, and 12 weeks after vaccination were stimulated in vitro with influenza A (H1N1) virus-infected autologous cells and then assayed for influenza virus-specific cytotoxicity using autologous virus-infected target cells. CTL responses to vaccination exhibited influenza A virus heterosubtypic cross-reactivity and were mediated primarily by CD8+ effector cells. Anti-influenza virus CTL activity was enhanced to a significantly greater extent by the liposome vaccine than by the control subvirion vaccine. It remains to be established whether the advantage of a liposomal formulation in terms of an improved CTL response is relevant to vaccine protective efficacy.

Increased anti-influenza A virus cytotoxic T cell activity following vaccination of the chronically ill elderly with live attenuated or inactivated influenza virus vaccine.

The possible enhancement of anti-influenza A virus memory cytotoxic T cell (CTL) responses to inactivated influenza virus vaccine by coadministration of intranasal live attenuated influenza A virus vaccine was investigated. Fifty elderly nursing home residents received inactivated trivalent influenza virus vaccine intramuscularly and simultaneously were randomly assigned to receive either bivalent live attenuated influenza A virus vaccine or saline placebo intranasally in a blinded fashion. A larger proportion of volunteers who received live attenuated virus vaccine than of those who received placebo experienced a postvaccination rise in anti-influenza A virus CTL activity (15 of 23 vs. 8 of 24; P < .05). Anti-influenza A virus cytotoxicity was primarily mediated by CD8+ T cells and was influenza A virus-specific and HLA-restricted. There was a possible advantage of administering live attenuated with inactivated virus vaccine because of enhanced memory anti-influenza A virus CTL activity.

Influenza A virus vaccines containing purified recombinant H3 hemagglutinin are well tolerated and induce protective immune responses in healthy adults.

This study evaluated the safety, immunogenicity, and protective efficacy of vaccines containing purified recombinant uncleaved hemagglutinin (rHA0) from influenza A/Beijing/32/92 (H3N2) virus. In a randomized, double-blinded trial, 127 adult volunteers were immunized with 15 micrograms of rHA0, 15 micrograms of rHA0 plus alum, 90 micrograms of rHA0, licensed subvirion vaccine, or saline placebo. The rHA0 vaccines caused fewer local adverse reactions than did the commercial subvirion preparation. Neutralizing hemagglutinin-specific antibody responses to 15 micrograms of rHA0 were comparable to those elicited by licensed vaccine, not enhanced by the addition of alum, and significantly increased by raising the rHA0 dose from 15 to 90 micrograms. Compared with placebo recipients, rHA0-vaccinated subjects had significantly lower rates of influenza A (H3N2) virus infection and illness during the epidemic winter season. These results suggest that influenza vaccines containing purified rHA0 may offer an advantage over licensed preparations containing egg-grown antigens by inducing equivalent protective immune responses while being potentially less reactogenic.

Effect of age on serum immunoglobulin G subclass antibody responses to inactivated influenza virus vaccine.

We previously reported an age-associated impairment of serum immunoglobulin G (IgG) antibody responses to inactivated influenza virus vaccine. The present study extends these observations by examining the IgG subclass distribution of vaccine responses measured by enzyme linked immunosorbent assay in healthy adults aged < 40 (young), 40-64 (middle-aged), and > or = 65 (elderly) years. Serological responses in all age groups showed antibodies that were predominantly IgG1 and secondarily IgG3. Influenza antigen-specific IgG4 titers did not change following vaccination, and antibodies of the IgG2 subclass were not detected in any serum specimens. Aging was associated with a significant impairment of IgG1, but not of IgG3, antibody production. Relative differences in the magnitude and frequency of response between IgG1 and IgG3 subclasses, which were present in young and middle-aged adults (viz., IgG1 > IgG3), were less apparent in the elderly. This observation was confirmed in a second analysis of IgG subclass-specific responses in a separate cohort of elderly vaccinees. These results suggest that the age-related impairment of humoral responses to inactivated influenza virus vaccine is primarily accounted for by differences in IgG1 antibody production, and that IgG3 antibodies make up a larger proportion of the overall serologic response in the elderly than they do in younger persons.

Vaccine-induced antibodies to heterologous influenza A H1N1 viruses: effects of aging and "original antigenic sin".

Prototype influenza A H1N1 viruses representing antigenically distinct Hsw1, H0, and H1 hemagglutinin variants that circulated during the early 1900s were used to measure cross-reactive serum hemagglutination inhibition antibodies elicited by contemporary inactivated virus vaccines in adults aged < 40 (young), 40-64 (middle-aged), or > or = 65 (elderly) years. Elevated titers of antibodies to Hsw1 and H0 antigens were present both before and after vaccination in higher proportions of middle-aged and elderly than young adults, whereas antibodies to more recent H1 antigens were prevalent in all age groups. Vaccine responses to heterologous H1N1 viruses were consistently reduced in frequency and magnitude with advancing age. Also, within each age group, antibody responses tended to diminish against progressively older heterologous antigens. These results confirm previous seroepidemiological surveys but suggest that preferential orientation of secondary antibodies toward priming epitopes ("original antigenic sin") is not responsible for the age-related impairment of antibody responses to influenza vaccine.

Increased immunogenicity of inactivated influenza virus vaccine containing purified surface antigen compared with whole virus in elderly women.

Thirty-eight elderly female subjects (aged 80 +/- 7 years, mean +/- standard deviation) were randomized to immunization with trivalent inactivated influenza virus vaccine containing either purified surface antigen (n = 18) or whole virus (n = 20) components from A/Texas/36/91 (H1N1), A/Beijing/353/89 (H3N2), and B/Panama/45/90 strains. Humoral and cellular immune responses were assessed by measuring serum hemagglutination inhibition antibodies and cytotoxic T lymphocyte (CTL) activity at 0 and 3 weeks postvaccination. Serological responses to both of the type A vaccine strains following immunization with surface antigen vaccine (SAV) were significantly more frequent and greater in magnitude than those induced by whole-virus vaccine. Antibody responses to the B/Panama component were modest and did not differ significantly between the two vaccines. Persons given SAV, but not those given whole-virus vaccine, had a small but significant increase in mean percent specific lysis of influenza A (H1N1) virus-infected autologous targets by peripheral blood mononuclear cells which were stimulated in vitro with influenza A (H1N1) virus. The H1N1-stimulated cytotoxic effectors induced by SAV were CD8+ and were not cross-reactive against H3N2-infected targets. Influenza B virus-specific CTL responses were not observed with either vaccine. These results suggest that currently available subunit influenza virus vaccines may offer an advantage over inactivated whole-virus preparations for inducing humoral and cellular immune responses in the elderly, although the CTL response may be too limited to be of physiological significance.

Effect of age on cytotoxic T lymphocyte memory as well as serum and local antibody responses elicited by inactivated influenza virus vaccine.

Healthy seropositive adults aged < 40 (n = 15), 40-64 (n = 15), and > or = 65 (n = 17) years were parenterally immunized with trivalent subvirion influenza virus vaccine, and their cellular and humoral immune responses were compared. Vaccination resulted in a significant enhancement of class I human leukocyte antigen-restricted influenza A cross-reactive cytotoxic T lymphocyte (CTL) memory. Elderly subjects had significantly lower baseline and peak postvaccination mean percentages of specific lysis of influenza A virus-infected autologous targets but nonetheless mounted CTL responses to vaccine that were comparable in magnitude to those of younger adults. Serologic responses and nasal IgG responses to each of 3 vaccine strains were reduced in magnitude and frequency with advancing age. Parenteral immunization was ineffective at inducing nasal wash IgA antibodies. Between 2 and 12 weeks after vaccination, serum and nasal antibody titers decreased modestly, although the rate of decline was comparable between age groups. The ability of elderly adults to mount CTL responses after influenza vaccination suggests that T cell effector mechanisms may be an important determinant of vaccine-induced protection against serious illness in this age group.

Influenza A virus-specific cytotoxic T lymphocyte activity declines with advancing age.

OBJECTIVE: To investigate whether influenza A-specific cytotoxic T lymphocyte (CTL) activity is reduced in elderly compared with younger adults. DESIGN: Case series comparing outcomes in young and elderly cohorts. SETTING: Saint Louis University Division of Geriatric Medicine. PARTICIPANTS: Healthy adult outpatients and staff members aged < 50 (young) or > or = 65 (elderly) years. METHODS: Peripheral blood mononuclear cells were assayed for CTL activity by a 51chromium release assay following 1 week of in vitro stimulation with influenza A/PR/8/34 (H1N1) virus. MEASUREMENTS: Percent specific lysis of autologous and allogeneic influenza virus-infected target cells. MAIN RESULTS: Specific lysis of autologous A/PR-infected targets was significantly lower in elderly compared to young subjects (P < 0.01), and exceeded 10% in a significantly lower proportion of elderly compared with younger subjects (P < 0.05), but was not influenced by a history of vaccination within the preceding 12 months. Cytotoxic effectors were class I human leukocyte antigen (HLA)-restricted and displayed heterosubtypic cross-reactivity but were unable to lyse influenza B-infected targets. CONCLUSIONS: These results demonstrate an age-related decline of influenza A virus-specific CTL activity and suggest that CTL responses to inactivated virus vaccine are of short duration.