Strain differences in the cytotoxic activity and TNF production of murine macrophages stimulated by lentinan.

The effect of lentinan, a glucan type immunomodulatory polysaccharide was studied on the antitumor cytotoxicity and on the TNF secretion of peritoneal macrophages in inbred H-2 congeneic mouse strains under in vivo and in vitro conditions. The cytotoxic activity and TNF secretion of murine macrophages was found to be elevated by lentinan in vitro and in vivo conditions. The effectiveness of lentinan to induce cytotoxicity and TNF secretion was highly influenced by the genotype of the host.

A simple, rapid and sensitive fluorimetric assay for the measurement of cell-mediated cytotoxicity.

A fluorimetric method using 4-methylumbelliferyl heptanoate (MUH) has been developed for detecting cell-mediated cytotoxicity and cell proliferation. The assay is based on the hydrolysis of the fluorochrome (MUH) by intracellular esterases of viable cells resulting in the production of highly fluorescent 4-methylumbelliferone that can be measured in a microplate fluorimeter. Because of a similarity to the principle of the widely used colorimetric MTT assay, a comparison was made between the two assays when measuring cell proliferation and LAK cell cytotoxicity to different target cell types.

Characterization of monoclonal antibodies to adenovirus type 35 hexon.

Twenty three monoclonal antibody-rich ascitic fluids (MIAFs) to human adenovirus (AV) type 35 hexon were studied by indirect ELISA using various tracer systems, passive haemagglutination (HA) as well as gel diffusion techniques. Eleven different human heterologous hexon types in addition to the homologous one, and two animal adenovirus (AV) hexons were used to determine the reactivity patterns (RPs) of the monoclonal antibodies (MoAbs). Based on the cross-reactivity with the different hexon types, the MoAbs exhibited genus, subgenus and type specificities; furthermore, a variety of intersubgenus and intertype specificities could be found.

The role of genetic factors in the immunomodulating effect of thymosin.

The possible role of hypothetical genetic factors involved in the immunomodulating effect of thymosin fraction 7 (T7) was investigated. The model system was the in vitro immunization of murine spleen cell cultures with sheep red blood cells (SRBC), and the generation of antigen specific B cells in T7 treated cultures was compared to that of control values. It was found that T7 treatment enhanced the plaque forming cell (PFC) response of BALB/c spleen cells, while it proved to be suppressive in CBA cultures.