No abstract

DNA vaccines are usually given by intramuscular injection or by gene gun delivery of DNA-coated particles into the epidermis. Induction of mucosal immunity by targeting DNA vaccines to mucosal surfaces may offer advantages, and an oral vaccine could be effective for controlling infections of the gut mucosa. In a murine model, we obtained protective immune responses after oral immunization with a rotavirus VP6 DNA vaccine encapsulated in poly(lactide-coglycolide) (PLG) microparticles. One dose of vaccine given to BALB/c mice elicited both rotavirus-specific serum antibodies and intestinal immunoglobulin A (IgA). After challenge at 12 weeks postimmunization with homologous rotavirus, fecal rotavirus antigen was significantly reduced compared with controls. Earlier and higher fecal rotavirus-specific IgA responses were noted during the peak period of viral shedding, suggesting that protection was due to specific mucosal immune responses. The results that we obtained with PLG-encapsulated rotavirus VP6 DNA are the first to demonstrate protection against an infectious agent elicited after oral administration of a DNA vaccine.

Our earlier reports demonstrated that Cynomolgus macaques vaccinated with either inactivated partially purified simian immunodeficiency virus (SIV), fixed SIV-infected C8166 (a human T lymphoblastoid cell line) cells, or fixed uninfected C8166 cells can be protected against a challenge infection with the 32H isolate of SIVmac 251 (grown in C8166) (Stott, E. J., W. L. Chan, K. H. G. Mills, M. Page, F. Taffs, M. Cranage, P. Greenway, and P. Kitchin. 1990. Lancet. 336:1538; Stott, E. J., P. A. Kitchin, M. Page, B. Flanagan, L. F. Taffs, W. L. Chan, K. H. G. Mills, P. Silvera, and A. Rodgers. 1991. Nature [Lond.]. 353:393). Protection is correlated with the levels of antibody response to cellular antigens in the human cells from which the virus immunogen was grown. However, the mechanism of protection is unclear. We report here the analysis of sera from these protected monkeys and demonstrate that there is positive correlation of protection with antibody response to the HLA class I molecule.

SUMMARYVirions of human cytomegalovirus were shown to contain two discrete membranes. An outer, loose fitting, membrane was sensitive to osmotic shock and could be partially removed by diluting buffered preparations of virions with water. Purified virions were shown, by SDS-polyacrylamide gel electrophoresis of virion membranes labelled by carbohydrate-specific procedures, to contain five glycoproteins with molecular weights of 52, 67, 95, 130 and 250, all × 103. Digestion of virions with endoglycosidases revealed that there were structural differences between the carbohydrate portions of the glycoproteins. All five glycoproteins were recognized by antibodies present in pools of human convalescent sera.

SUMMARYThree disulphide cross-bridged glycoprotein complexes were immunoprecipitated from purified human cytomegalovirus envelopes using a monoclonal antibody with a specificity for a glycoprotein of tool. wt. 52 x 103. These complexes were isolated by electroelution after polyacrylamide gel electrophoresis (PAGE) under non-reducing conditions. Compositional analysis of each complex by PAGE under reducing conditions showed that at least two distinct complexes, one containing glycoproteins with mol. wt. of 52 x 103 and 95 x 103 and the other with glycoproteins of 52 x 103 and 130 x 103, were present. The results obtained indicated that one of these complexes could also exist as a dimer.