Evaluation of an orally administered vaccine, using hydrogels containing bacterial exotoxins of Pasteurella haemolytica, in cattle.

Poly(methacrylic acid) hydrogels were tested for oral delivery of a vaccine against Pasteurella haemolytica infection in cattle. Culture supernatants of P haemolytica, the most common bacterium associated with pneumonia in cattle, were used as the antigens in the vaccine. Hydrogels containing culture supernatants were administered orally to calves.

Stimulation of human neutrophil Fc receptor-mediated phagocytosis by a low molecular weight cytokine.

Human neutrophil Fc receptor-mediated phagocytosis can be markedly enhanced by a low m.w. (less than 10,000) heat-labile cytokine(s) derived from specifically stimulated human mononuclear cells and from a human T cell line, MO(t).

Two phenotypically distinct suppressor T cell subpopulations inhibit the induction of B cell differentiation by phytohemagglutinin.

Human B lymphocytes can be induced to differentiate into antibody-secreting plasma cells by Leu-3+ T lymphocytes stimulated with pokeweed mitogen (PWM), a polyclonal T cell activator. In contrast, other polyclonal T cell mitogens, such as phytohemagglutinin (PHA), also activate Leu-3+ T cells but are relatively ineffective inducers of B cell differentiation. We have performed a series of experiments to investigate the mechanism underlying this apparent paradox.

Regulation of the growth and differentiation of a human monocytic cell line by lymphokines. I. Induction of superoxide anion production and chemiluminescence.

The U937 human monocytic cell line was studied to determine its ability to generate a respiratory burst after stimulation with phorbol myristate acetate (PMA) or opsonized zymosan. U937 cells cultured in normal medium produced virtually no superoxide anion or chemiluminescence in response to either stimulus. In contrast, U937 cells cultured in medium containing soluble factors from activated lymphocytes produced significant O2- and chemiluminescence when stimulated with PMA or opsonized zymosan.

Identification of neutrophil subpopulations with monoclonal antibodies.

Two monoclonal antibodies have been produced by the hybridoma technique that recognize subpopulations of human neutrophils. The antibodies, termed 1B5 and 4D1, react with a mean percentage of 57% and 51% of peripheral blood granulocytes, respectively. The antigens recognized appear to be neutrophil specific in that these antibodies do not react with eosinophils, platelets, erythrocytes, monocytes, or nonadherent peripheral blood mononuclear cells.