Response In Young Mice Research Articles

Vaccination in the Neonatal Period and Early Infancy

Immune maturation is responsible for a progressive increase in antibody responses that can be elicited during the first year of life, such that neonatal immunization may currently not be expected to induce strong antibody responses. In contrast, B and T cell priming can be induced very early in life, without interference of maternal immunity. Strong IL-5 and IL-13 responses in young mice, and limited IL-12 and IFN-γ release capacity by early life APC and T cells both in young mice and infants, could contribute to the severity of infections with intracellular pathogens in early life. It calls for evaluation of novel delivery systems, adjuvants and/or prime-boost immunization strategies capable to meet the challenge of both strong neonatal immuno-genicity and acceptable reactogenicity. The extent to which early life murine immunization models may be useful for precünical evaluation of infant responses is outlined in this review.

The in vivo effects of neutralizing antibodies against IFN-γ, IL-4, or IL-10 on the humoral immune response in young and aged mice

In the present study we investigated whether age-related changes in the composition and functional properties of murine CD4 + T cells are reflected in vivo by a changed humoral response to influenza vaccine in aged mice. After the primary immunization, the titers of influenza-specific IgM, IgG1, IgG2a, and IgG2b, but not of IgG3 and IgE, were significantly reduced in aged mice compared to young mice. Treatment of aged mice with anti-IFN-γ, anti-IL-4, or anti-IL-10 resulted in levels of IgM and IgG1 comparable to those found in young mice, whereas IgG2a and IgG2b were further decreased. After the booster immunization IgE was significantly enhanced in aged mice, whereas no differences were observed with regard to the other isotypes. During the primary response in young mice, anti-IFN-γ stimulated IgG1 and IgE, whereas an inhibition of IgG2a, IgG2b, and IgG3 was observed. Anti-IL-4 caused a decrease only in IgG3 while anti-IL-10 increased IgM and IgG1 and decreased IgG2b and IgG3. During the primary response in aged mice, all anti-cytokine antibodies enhanced IgM and IgG1 while IgE was only enhanced by anti-IL-10. By contrast, IgG3 was inhibited by anti-IFN-γ and anti-IL-10. Anti-cytokine treatment of young mice increased all isotypes, except IgG3, in the secondary response, whereas the secondary response in aged mice was largely insensitive to anti-cytokine treatment. These data therefore support the idea that the in vivo effects of cytokines on isotype switching are dependent on the differentiation stage of B cells which may be different in young and aged mice.

Sendai viral pneumonia in aged BALB/c mice

Sendai virus (SV) infection in aged BALB/c mice was evaluated as a natural model for age-associated susceptibility to viral pneumonia. Young (2 month-old) and aged (22–24 month-old) BALB/c mice were inoculated intranasally with 100 median pneumonia doses (PD 50) of SV and examined at 6, 10, and 20 days by virus titration, immunohistochemistry, histopathology, and serology. The aged mice had significantly higher virus titers in lung, prolonged infection, delayed development, and resolution of pneumonia and significantly lower serum antibody titers. In a second experiment, the responses of young mice were compared to intermediate-aged mice (11–13 and 17–18 months old). The intermediate-aged mice had some characteristics of young mice and others of aged mice. The results indicate that SV infection can be used to study aging-associated susceptibility to a pneumotropic virus in a natural host, and that susceptibility of mice to viral pneumonia increases gradually during aging.

Preparation, characterization, and immunogenicity of conjugates composed of the O-specific polysaccharide of Shigella dysenteriae type 1 (Shiga's bacillus) bound to tetanus toxoid

The background for developing conjugate vaccines for shigellosis composed of the O-specific polysaccharide (O-SP) bound to a protein is described elsewhere (C. Y. Chu, R. Schneerson, and J. B. Robbins, submitted for publication). Briefly, there is direct evidence for type (lipopolysaccharide [LPS])-specific protection after infection with the wild type or with attenuated strains of shigellae. Prospective studies of Israeli armed forces recruits show a correlation between preexisting serum immunoglobulin G (IgG) LPS antibodies and resistance to shigellosis (D. Cohen, M. S. Green, C. Block, R. Slephon, and I. Ofek, J. Clin. Microbiol. 29:386-389, 1991). In order to elicit IgG LPS-specific antibodies to Shigella dysenteriae type 1, the O-SP of this pathogen was purified and bound to tetanus toxoid (TT) by three schemes. The most immunogenic used a modification of a published method (C. Y. Chu, R. Schneerson, J. B. Robbins, and S. C. Rastogi, Infect. Immun. 40:245-256, 1983). The resultant O-SP-TT conjugates were stable and elicited high levels of IgG O-SP antibodies and booster responses in young mice when injected subcutaneously in saline at 1/10 the proposed human dose. Adsorption onto alum or concurrent administration with monophosphoryl lipid A enhanced both the IgG and IgM antibody responses to the O-SP of the conjugate; both the nonadsorbed and adsorbed conjugates elicited higher rises of IgG than of IgM antibodies. Clinical evaluations of S. dysenteriae type 1 O-SP-TT conjugates are planned.

Improvement of hepatitis B vaccine by the use of a new adjuvant

Humoral and cellular immune responses of mice and guinea-pigs to hepatitis B virus surface antigen when alum-precipitated or administered with Syntex Adjuvant Formulation (SAF) were compared. Two doses of HBsAg in SAF were sufficient to elicit antibody responses, and using SAF the dose of antigen could be reduced to one-tenth of that required to elicit antibody responses by alum-adjuvanted HBsAg. The use of SAF increased and made more consistent the antibody responses in young mice and in strains of mice with inherited low responses to HBsAg. Cellular responses to HBsAg were more consistently observed when SAF was used than when alum was used. SAF increased the formation of IgG2a antibodies in mice except in the B10.M strain; antibodies of this isotype activate complement and act synergistically with antibody-dependent effector cells more efficiently than antibodies of other isotypes. If SAF proves acceptable for human use it could improve vaccines against hepatitis B virus.

Physiology of IgD. VIII. Age-related decline in the capacity to generate T cells with receptors for IgD and partial reversal of the defect with IL 2.

In previous studies we have shown that T cells from young mice can be induced to express receptors for IgD (T delta cells) after in vivo or in vitro exposure to IgD or IL 2. In the present study, mice of three different strains were used to study the effects of aging on the ability of splenic T cells to express such receptors. It is shown that T cells from mice older than 18 mo of age are deficient with respect to their ability to express receptors for IgD after in vivo or in vitro exposure to IgD. Similarly, IFN-gamma induces T delta cells in young but not in aged mice. In contrast, T delta cells can be induced in aged mice with IL 2, although to a lower percentage than in young mice. In agreement with our previously reported findings, the current study demonstrates the immunoaugmenting effect of IgD injections on the antibody response in young mice. This effect is absent in aged mice and thus correlates with the failure of IgD to induce T delta cells in such animals.

Hormonal modulation of responses to thymus-independent and thymus-dependent antigens in autoimmune NZB/W mice.

Previous work suggested that gonadal steroids influence immunity through the thymus, but the mechanisms were unclear. To investigate the effects of these hormones on immune responses to T1 and TD antigens in autoimmune mice, we studied hybrid NZB/W mice and the nonautoimmune DBA/2 strain. Mice castrated at 14 days of age were implanted with Silastic capsules releasing, in adults, physiologic levels of E2 in males or Te in females. Sham-operated controls received empty capsules. Splenic PFC were quantified 4 to 5 days after challenge with the TI2 antigen TNP-Ficoll, the TI1 antigen TNP-LPS, or the TD antigen SRBC. Young castrated NZB/W males implanted with E2 had striking enhancement of IgM responses to TNP-Ficoll when compared to castrated Te-treated females and comparable sham-operated controls of both sexes. E2 also stimulated responses to TNP-LPS. In response to challenge with SRBC, young E2-treated NZB/W males had a consistent trend to increased IgM PFC, and the stimulatory effect of E2 on IgG plaques was variable. Physiologic doses of Te had no consistent effect on responses in young mice. In old female NZB/W mice, Te caused PFC response after immunization with TNP-Ficoll to resemble age-matched NZB/W males. As sham-operated NZB/W females grew older, PFC responses to SRBC fell. This age-related phenomenon was delayed, however, in female castrates implanted with Te. In contrast, Te clearly suppressed responses to TNP-LPS. Implantation of E2 did not alter responses to TNP-Ficoll, TNP-LPS, or SRBC in nonautoimmune DBA/2 males. This finding suggested that exogenous E2 given in physiologic doses did not influence immunologic responsiveness in a normal strain to the degree seen in hormone-sensitive NZB/W mice. It was concluded that E2 enhanced responses to a variety of exogenous antigens in autoimmune NZB/W mice. The most consistent E2-induced increase in PFC response was observed with TI antigens, suggesting that E2 exerted its effects on B cells or Ts.

Supplemental zinc restores antibody formation in cultures of aged spleen cells.

The in vitro production of antibody to T-dependent antigens is depressed as a function of age. The addition of supplemental zinc to cultures of cells from young adult, middle-aged, and immunodepressed-aged mice enhances antibody production. The responses of young mice are enhanced 30 to 40%, but the responses in cultures from aged mice are increased 5- to 12-fold and the maximum response achieved is often equivalent to that of young, fully competent mice. The addition of zinc at varying times during the culture period suggests that zinc affects early events in the activation of antibody-forming cells.

The immune response of aged mice to influenza: Diminished T-cell proliferation, interleukin 2 production and cytotoxicity

In view of the fact that T lymphocytes play a key role in the recovery from viral infections, and that many immune functions involving T cells show a decline in aged individuals, we examined the ability of old mice to mount a T-cell response to influenza virus. Both primary and secondary cytotoxic T-lymphocyte (CTL) responses following in vivo immunization with influenza virus were minimal in old mice at the time point of peak response in young mice. Analysis of CTL activity generated in an in vitro microculture system revealed both a diminished proliferative response and a decrease in Interleukin 2 (IL-2) production in “old” compared to “young” cultures following stimulation with virus. Furthermore, addition of exogenous IL-2 at the initiation of the culture period augmented both subtype-specific and A-strain cross-reactive CTL activity of old spleen cells. Finally, exogenous IL-2 increased the lower proliferative response of the old cultures. These findings, if also true for elderly humans, might have broad clinical relevance to the problem of suitable prophylactic approaches to influenza infection in the elderly.

Conditioned avoidance responses of young mice and offspring of mice treated with neuroleptic or mutagenic agents.

Conditioned avoidance response (CAR) tests were used to determine the effects of perinatal exposure to three neuroleptic drugs and an antineoplastic agent in mice. In one experiment, mice were given sc injections of haloperidol at 1.25 mg/kg.d or trifluoperazine at 12.5 mg/kg.d for 2 wk, starting when they were 4 d old. In additional groups, nursing dams were given haloperidol at 5 mg/kg.d or trifluoperazine at 25 mg/kg.d for 2 wk during lactation. CAR tests were begun when offspring were 40 d of age. No statistically significant evidence of impairment in the learning ability of any group was found. In a second experiment, hybrid male mice were treated with a single ip injection of triflupromazine at 50 mg/kg or triethylenemelamine at 0.2 mg/kg and were mated 2, 4, and 6 wk after dosing. The male offspring were tested for learning ability at 40 d of age. No statistically significant differences in CAR values were observed in offspring of triflupromazine-treated males. CAR values of offspring of triethylenemelamine-treated males mated 4 wk after dosing were significantly higher than those of controls.

The effect of cyclophosphamide on MSV-H oncogenesis

The effect of cyclophosphamide on MSV-H oncogensis and the immune response of young mice has been investigated. A single, sublethal dose (100 and 50 mg/kg of cyclophosphamide) in 8-day-old mice given 24 h before or after MSV-H infection led to an earlier and lower incidence of tumours in comparison with controls infected only with MSV-H. The protective effect of cyclophosphamide, and the mechanism of action of both cyclophosphamide and MSV-H on the target cells, mesenchymal cells in rapid replication, as well the immunological implications of the findings are discussed.

幼若マウスの抗体産生能と成熟過程における各血清分画の変動

1. Repeated immunizations with heat-killed as well as chrome alum-treated vaccines of Salmonella enteritidis failed to produce marked immunological responses in young mice of less than 20 days old. Circulating antibody titers were found to reach high levels eventually as the animals gradually matured.2. On the other hand, a prenatal inoculation of the vaccine administered to fetus mice evoked neither the transitory depression of immune response nor the permanent tolerance against the specific antigens.3. Statistical analyses were made with paper electrophoresis of sera taken from young mice at various times during the first 6 weeks of life; the neonatal high gamma globulin level dropped after birth, reaching the lowest levels at 3 to 4 weeks, followed by a slow rise up to 6 weeks of age. The serum albumin contents increased significantly during the experimental period, whereas alpha plus beta globulin remained at the same low level throughout the period.4. The fall in gamma globulin level in early life was, then, compared with the rate of disappearance of passively administered homologous antibodies. It was tentatively concluded that even though the total amount of gamma globulin was decreasing in newborns there must be a small quantity of new gammaglobulin being formed at the same time.5. A reasonable conclusion may be that the most probable cause of the poor antibody formation in young mice can be ascribed to the immature ability of the animals to produce new gamma globulin.