The role of class II major histocompatibility antigens in classical antigen-presenting cells has been described (Unanue (1984) Annu. Rev. Immunol. 2, 395-428; Watts and McConnell (1987) Rev. Immunol. 5, 461-475). Whether enterocytes, which also express class II antigens, can act as antigen-presenting cells in vivo is not known. One pre-requisite for a role for enterocytes in antigen presentatio...

The constraint of fitting a diverse repertoire of antigen specificities in a limited total population of lymphocytes results in the frequency of naive cells specific for any given antigen (defined as the precursor frequency) being below the limit of detection by direct measurement. We have estimated this precursor frequency by titrating a known quantity of antigen-specific cells into naive reci...

A decline in 5'-nucleotidase production was observed in short-term tissue culture of guinea pig alveolar, peritoneal, splenic, and liver macrophages during exposure to 10(2) microM rifampicin, 1 microM levamisole, or 10 micrograms of cytoplasmic protein antigen extracted from Mycobacterium microti. Liver macrophage 5'-nucleotidase production was more significantly inhibited by the three agents....

Naturally evolving antibodies attain elevated affinity in germinal centers (GCs).[1] In these dynamic open micro-structures, competition between B cell clones and their somatic mutants drives an increase average across individual populations of up to a few thousand cells. Such evolutionary learning the antigenic target (known as maturation), however, eventually saturates. Most notably, saturati...

Safety and antigenicity of a purified preparation of Salmonella typhosa Vi antigen was evaluated in human volunteers. Dosages of Vi antigen at 25, 50, and 100 mug were less toxic than U.S. standard typhoid vaccine (lot 6A) containing 5 X 10(8) bacteria per dosage. Vi antigen in comparison with the standard typhoid vaccine induced higher hemagglutinating antibody but lower bactericidal antibody ...

In the last decades researchers had focused on developing a vaccine against tick based on protective antigen. Recombinant vaccines based on concealed antigen from Boophilus microplus have been developed in Australia and Cuba by the name of TICKGARD and GAVAC (De La Fuente and Kocan, 2006). Further studies on this antigen have shown some extent of protection against other species (De Vos et al.,...