T helper cell cytotoxicity

Conference · Fri Feb 28 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5433573

Penna, A; Glasebrook, A

It has recently been shown that helper T cells (Lyt2/sup -/, L3T4/sup +/) can express cytolytic activity when activated by antigen (Ag). The authors have studied the phenomenon of T helper cell cytotoxicity using cloned lines of Ag-reactive T cells and T hybrids. Cytotoxicity was determined by coculture of T cells with /sup 51/Cr-labelled Ag presenting cells (APC) and/or non-APC (bystander cells). A high frequency of Ag-specific L3T4/sup +/ T cell clones (> 90%) and hybrids (> 50%) were found to be cytotoxic. Cytotoxicity as determined by /sup 51/Cr release was maximal at 20 hr with little or no cytotoxicity detectable at 6 hr. Target cells, either APC or bystander cells, were killed provided the T cells were stimulated by Ag. Not all of the B cells used as APC were susceptible targets even if able to promote bystander killing. Monoclonal antibodies directed against L3T4, LFA-1 and T cell receptor molecules were able to block the cytotoxicity indicating a requirement for specific activation of the T cells. Cyclosporin A (CsA) reduced the cytotoxic activity of helper T hybrids and clones, while it did not affect the cytotoxic activity of Lyt2/sup +/, L3T4/sup -/ cytolytic T cell (CTL) clones. The delayed expression of cytotoxic activity, the lysis of bystander cells and inhibition by CsA suggest that the cytolytic mechanism is mediated by a soluble factor and different from the cytolytic mechanism of CTL. The phenomenon of cytotoxic T helper cells may be relevant to suppression of B cell immune responses in vivo.

• Research Organization: Lilly Research Labs., La Jolla, CA
• OSTI ID: 5433573
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:3; ISSN FEPRA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANTIBODIES
ANTIGENS
BETA DECAY RADIOISOTOPES
BIOLOGICAL FUNCTIONS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CELL CULTURES
CELL KILLING
CHROMIUM 51
CHROMIUM ISOTOPES
CLONE CELLS
CONNECTIVE TISSUE CELLS
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
FUNCTIONS
HYBRIDIZATION
IMMUNE REACTIONS
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LEUKOCYTES
LYMPHOCYTES
LYSIS
MATERIALS
MEMBRANE PROTEINS
MONOCLONAL ANTIBODIES
NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
RECEPTORS
SOMATIC CELLS
TRACER TECHNIQUES