Effects of different lipoproteins on the proliferative response of interleukin-2-activated T lymphocytes and large granular lymphocytes.
1. T lymphocytes and large granular lymphocytes internalized chylomicrons, very low-density lipoprotein, low-density lipoprotein, high-density lipoprotein and acetyl modified low-density lipoprotein through different receptors as assessed by flow cytometry. The observed internalization ranged from 8% to 20%. 2. All lipoproteins induced proliferative responses in T lymphocytes and large granular lymphocytes at optimum concentrations (40 micrograms of protein/ml for all lipoproteins except high-density lipoprotein). Chylomicrons, very low-density lipoprotein and low-density lipoprotein increased T-lymphocyte proliferative response by fourfold while inducing respectively a seven-, nine- and sevenfold increment in large granular lymphocytes. Similarly, high-density lipoprotein and acetyl modified low-density lipoprotein respectively induced a nine- and sevenfold increment in T cells and a 17- and eightfold increment in large granular lymphocyte proliferative response. 3. Both cell types internalized more lipoprotein when they were stimulated with interleukin 2. Chylomicrons and low-density lipoprotein internalization was increased threefold and very low-density lipoprotein internalization twofold, while high-density lipoprotein internalization was unchanged in both cell types. Acetyl modified low-density lipoprotein internalization was fourfold higher in large granular lymphocytes only. 4. The proliferative response of interleukin-2 stimulated cells was different from that of unstimulated cells. Chylomicrons and very low-density lipoprotein induced a sixfold increment in T-cell proliferative response but only a fourfold increment in large granular lymphocytes. Low-density lipoprotein and acetyl modified low-density lipoprotein induced respectively a sevenfold and eightfold increment in T cells and a eightfold and threefold increment in large granular lymphocyte proliferative response. High-density lipoprotein did not affect T-lymphocyte proliferative response while inducing a twofold increase in large granular lymphocytes. 5. Lipoproteins are important in the proliferative response of unstimulated and interleukin-2-stimulated cells.
Institute of Immunology, Faculty of Medicine, Central University of Venezuela, Caracas.
J B
JB
De Sanctis
I
I
Blanca
N E
NE
Bianco
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D008074:Lipoproteins / Q000378:metabolism*; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018110:Receptors, Lipoprotein / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
D007376:Interleukin-2; D008074:Lipoproteins; D018110:Receptors, Lipoprotein