PubMed Health⌕ Search

Biomedical subjects

A H Malakian

Publications and source records attributed to A H Malakian.

4 recordsLinked to original sources
PubMed1977

The host response in secondary hydatidosis of mice. II. Cell mediated immunity.

The presence of cell mediated immunity to Echinococcus granulosus antigen was detected in syngeneic mice with secondary hydatidosis. Significant increases of thymidine uptake were observed in spleen cells from infected animals exposed to protoscolex or hydatid fluid antigens. A definite decrease in the number and size of cysts occurred in mice following the simultaneous intraperitoneal injection of viable protoscolices and a suspension of 1 x 10(7) sensitized spleen cells.

Animals↗
PubMed1975

A potent antimitogenic factor from group A streptococci.

A cytoplasmic component from group A streptococci produced complete suppression of human lymphocyte transformation induced by phytohaemagglutinin or the mixed lymphocyte reaction in vitro. It also suppressed antibody-forming cells in mice against sheep erythrocytes. The active substance was eluted as second and third fractions form Sephadex G-200 chromatography of the 100,000 g supernatant of sonically ruptured group A streptococci. The antimitogenic activity was not susceptible to trypsin, pronase, RNase or DNase digestion, but the activity was completely lost when it was sequentially digested, first with RNase and DNase and then with pronase. The active substance was not antigenic nor heat-labile at 56 degrees. It may be a protein component of a nucleoprotein.

Animals↗
PubMed1971

Biological characterization of an immunosuppressant from group A streptococci.

A component in extracts of Group A streptococci suppresses antibody formation in mice against heterologous erythrocyte and protein antigens. Large doses are not toxic and repeated injection does not change its effectiveness. It is most effective when injected 1 or 2 days before antigen and it is not suppressive when given after antigen. The active factor occurs as a large polydisperse complex and activity can be increased 10- to 25-fold by filtration through Sepharose 2B. Both direct (gammaM) and indirect (gammaG) antibody-forming cells are suppressed in primary and secondary responses. Injection before a primary response does not reduce memory cell development. It increases rather than depresses the "background" antibody-forming cells to sheep erythrocytes, and is equally effective if injected intraperitoneally or intravenously. Ribonuclease increases activity while deoxyribonuclease has no effect. Proteases destroy immunosuppressive action.

Animals↗