Bacterial induction of human activated lymphocyte killing and its inhibition by lipopolysaccharide (LPS).
Peripheral blood lymphocytes were incubated with glutaraldehyde-fixed Salmonella bacteria. This resulted in rapid activation of nonspecific cytotoxic potential of the lymphocytes. Both originally noncytotoxic, high-density Percoll-fractionated cells, and cytotoxic natural killer (NK) cell-enriched low-density cells were activated. The induction of originally noncytotoxic cells into activated killer (AK) cells was apparently independent of interferon (IFN), whereas the activation of the NK cell-enriched fractions also involved IFN production. Neither the AK nor NK activity were associated with significant bactericidal activity. The IFN-independent induction of AK activity was not dependent on the O-antigenic polysaccharide part of the lipopolysaccharide (LPS) on the bacterial cell surface, because both smooth (S) strains with differing O-antigenic structures (S-4,12 and S-6,7) and a rough (Re) strain without O-antigen were effective inducers. Isolated LPS, and especially alkali-hydrolyzed (O-deacylated, detoxified) LPS (ALPS) interfered with the induction of cytotoxicity. At concentrations of 10 to 30 micrograms/ml, ALPS totally inhibited the induction of AK activity without affecting the endogenous NK activity. Thus contact with bacteria can lead to the emergence of AK cells, and a bacterial product can effectively block this activation. These phenomena stress the complexity of interactions with host defenses that can take place during bacterial infection.
J
J
Tarkkanen
H
H
Saxén
M
M
Nurminen
P H
PH
Mäkelä
E
E
Saksela
D000942:Antigens, Bacterial / Q000276:immunology*; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007372:Interferons / Q000096:biosynthesis; D007694:Killer Cells, Natural / Q000276:immunology / Q000382:microbiology; D004915:Leukemia, Erythroblastic, Acute / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008213:Lymphocyte Activation; D012475:Salmonella / Q000276:immunology* / Q000502:physiology; D013997:Time Factors
D000942:Antigens, Bacterial; D007166:Immunosuppressive Agents; D008070:Lipopolysaccharides; D007372:Interferons