Maternal allergen immunization during pregnancy in a mouse model reduces adult allergy-related antibody responses in the offspring.

BACKGROUND: The immune status and allergen exposure of the mother may influence the immune response in the offspring after birth. This relationship may be important both for allergen avoidance strategies and, alternatively, for allergy prophylaxis by allergen exposure of the mother. OBJECTIVE: The aim of the present study was to investigate the effect of allergen immunization of the mother during pregnancy and postpartum, in relation to the allergy-related immune response (IgE) and the non-allergy-related (IgG2a) response in the offspring. METHODS: Pregnant NIH/OlaHsd females were immunized three times during pregnancy and one time postpartum with ovalbumin and the adjuvant Al(OH)3, and the offspring's ovalbumin-specific IgE, IgG1 and IgG2a responses were measured after challenge with the same allergen as young adults. Ovalbumin-specific IgE, IgG1 and IgG2a responses were also analysed in offspring of NIH/OlaHsd females immunized once at different times during pregnancy: about 3 days into pregnancy, mid-pregnancy (10 days into pregnancy) and about 4 days before giving birth (17 days into pregnancy). RESULTS: Allergen immunization of mother during pregnancy and postpartum significantly reduced the IgE response in the progenies, whereas the IgG2a response to the same allergen was increased. Allergen immunization of the mother 3 days into pregnancy resulted in a significantly lower IgE response in offspring compared with the response in offspring of non-immunized mothers and in offspring of mothers immunized 17 days into pregnancy. CONCLUSIONS: Maternal allergen immunization might favour selection for an allergen-specific Th1-dependent antibody response in the offspring. Our results indicate that IgE suppression is stronger after maternal allergen exposure during early pregnancy than after exposure in late pregnancy.

Human antibody response to a pneumococcal vaccine in SCID-PBL-hu mice and simultaneously vaccinated human cell donors.

Severe combined immunodeficient (SCID) mice were transplanted intraperitoneally with human peripheral blood lymphocytes (PBL) from nine healthy human donors (SCID-PBL-hu mice). None of the donors had ever received pneumococcal vaccine. Ten days after transplantation, 62 out of 111 transplanted mice and six of the nine donors were vaccinated with a 23-valent pneumococcal polysaccharide vaccine. For each donor, human IgG was detected in 91.7-100% of the SCID-PBL-hu mice, whereas specific human IgG antipneumococcal antibodies were demonstrated in 16.7-100% of the vaccinated SCID-PBL-hu mice. Most of the mice transplanted with cells from the same donor showed similar antibody response patterns in terms of kinetics and antibody levels. A significant antibody response was only obtained in mice that received cells from donors with relatively high antipneumococcal antibody levels at the time of transplantation, or donors that showed a substantial increase in antibody levels after vaccination. The immune response in the SCID-PBL-hu mice did not always reflect the ability of the respective donor to produce antipneumococcal antibodies. The donor dependency of the antipneumococcal antibody response has great practical importance for the use of the SCID-PBL-hu model. Donors should not be chosen randomly. By selecting donors whose cells have been found to result in successful engraftment, functional SCID-PBL-hu mice can be obtained for the study of human immune responses and function in an in vivo experimental model.