Detection of Progeny Immune Responses after Intravenous Administration of DNA Vaccine to Pregnant Mice

A number of factors influence the development of tolerance, including the nature, concentration and mode of antigen presentation to the immune system, as well as the age of the host. The studies were conducted to determine whether immunizing pregnant mice with liposome-encapsulated DNA vaccines had an effect on the immune status of their offspring. Two different plasmids (encoding antigens from HIV-1 and influenza virus) were administered intravenously to pregnant mice. At 9.5 days post conception with cationic liposomes, injected plasmid was present in the tissues of the fetus, consistent with trans-placental transfer. When the offspring of vaccinated dams were immunized with DNA vaccine, they mounted stronger antigen-specific immune responses than controls and were protected against challenge by homologous influenza virus after vaccination. Moreover, such immune responses were strong in the offspring of mothers injected with DNA plasmid 9.5 days after coitus. These results suggest that DNA vaccinated mothers confer the antigen-specific immunity to their progeny. Here we describe the methods in detail as they relate to our previously published work

Differential regulation of Th1 and Th2 cells by p91–110 and p21–40 peptides of the 16-kD α-crystallin antigen of Mycobacterium tuberculosis

Permissively recognized peptides which can activate lymphocytes from subjects with a variety of class II HLA types are interesting diagnostic and vaccine candidates. In this study we generated T helper clones reactive to the permissively recognized p21–40 and p91–110 peptides of the 16-kD heat shock protein of Mycobacterium tuberculosis. All the clones specific for p91–110 secreted interferon-gamma (IFN-γ) and were of the Th1 phenotype. By contrast, the p21–40 peptide favoured the generation of IL-4-producing clones. Antibody blockade established that the peptide-specific Th clones could either be DR-, DP- or DQ-restricted. Thus, two permissively recognized sequences p21–40 and p91–110 from the same mycobacterial antigen can drive the differentiation of functionally distinct T helper subsets. Attempts to immunize against tuberculosis should bear in mind epitope specificity if a favourable Th subtype response is to be generated