Identification of Neospora antigens recognized by CD4(+) T cells and immune sera from experimentally infected cattle

Neospora caninum is recognized as a major cause of infectious abortion in c attle. Very little is known about immunity to Neospora. Cell mediated respo nses have previously been shown to be important in the development of prote ctive immunity to the closely related parasite Toxoplasma gondii, and may t herefore be an important component in the immune response to Neospora. In t his paper we report that a group of low molecular weight NCI strain tachyzo ite antigens (less than or equal to 30 kDa) separated by SDS PAGE and bound to nitrocellulose membrane stimulated proliferation in vitro of CD4(+) T c ells from calves experimentally infected with N. caninum. Proliferation was accompanied by production of high concentrations of IFN gamma. Several of these antigens were also recognized by antibody produced in these animals. As the most effective vaccines require the stimulation of both humoral and cell mediated immune responses, these antigens may be important in the deve lopment of a vaccine against neosporosis.