B7-1, IFN gamma and anti-CTLA-4 co-operate to prevent T-cell tolerization during immunotherapy against a murine T-lymphoma.

We previously reported on a murine T lymphoma cell line, BW-Sp3, with inherent immunogenicity. BW-Sp3 tumors can elicit an anti-tumor CD8(+) CTL response capable of mediating a regression of subcutaneous tumors. However, this immune response is inadequate to eliminate cancer cells completely in a significant percentage of the recipients, resulting in progressing tumors.

Attenuation of Trypanosoma brucei is associated with reduced immunosuppression and concomitant production of Th2 lymphokines.

Mechanisms regulating resistance to African trypanosomes were addressed by comparing the immune responses of mice infected with attenuated Trypanosoma brucei brucei lacking the phospholipase C gene (PLC-/-) and those of mice infected with wild-type (WT) parasites. Inhibition of concanavalin A (ConA)-induced T cell proliferation occurred in spleen and lymph nodes of PLC-/-- and WT-infected mice. Although suppressive cells were elicited in spleen and lymph nodes of WT-infected animals, such cells were not detected in lymph nodes of PLC-/--infected mice.

Increased IL-12 P40 homodimer secretion by spleen cells during in vivo growth of the BW-19 T cell hybridoma accompanies suppression of natural immunity.

The high capacity of the T cell hybridoma BW-19 to metastasize to the spleen, despite its high and moderate sensitivity to lysis by macrophages and natural killer (NK) cells, respectively, appears to be linked to its capacity to suppress local resident NK cell and macrophage activity. Such suppression of splenic NK cell and macrophage activity is accompanied by an increased production of the p40 subunit of interleukin-12 (IL-12) by spleen cells. Closer examination revealed that most of the p40 subunit is present under the form of the homodimer (p40)2, whereas the heterodimeric form of IL-12 is present only in small amounts.

Metastasis of mouse T lymphoma cells is controlled by the level of major histocompatibility complex class I H-2Dk antigens.

In vivo inoculation of a low metastatic BW 5147 derived T-cell lymphoma variant into syngeneic mice, had led to the generation of a highly metastatic variant. The shift towards a more metastatic phenotype is accompanied by an increase in major histocompatibility class I H-2Dk antigen expression. This suggests that H-2Dk antigens may control the metastatic potential of BW T lymphoma cells.

A monoclonal antibody-based ELISA for the detection of circulating excretory-secretory antigens in Taenia saginata cysticercosis.

A series of monoclonal antibodies (MoAb) produced against excretory and secretory products from 10- and 20-week-old Taenia saginata cysticerci were tested for their ability to detect circulating antigen in a double antibody sandwich enzyme-linked immunosorbent assay (ELISA). Two MoAb, 12G5 and 2H8, proved to be highly reactive with the tegument of viable T. saginata cysticerci and recognized antigenic components of 65, 87 and 100 kDa in immunoblotting.