Effects of in vitro prepared immune complexes on rat adipose tissue lipoprotein lipase.
The possibility that circulating immune complexes (IC) could modify lipoprotein lipase (LPL) activity or release was explored in in vitro systems. IC were precipitated at antibody-Ag equivalence by using specific rabbit antisera and Ag from inactivated rubella virus and hemagglutinins from purified whole virions from three prototype strains of influenza (A/Brazil, A/Bangkok, and B/Singapore) as well as from a combined diphtheria and tetanus toxoid adsorbed with inactivated pertussis. After resolubilization, these IC were exposed to delipidated homogenates of rat epididymal fat pads before assay for LPL activity. LPL activity was stimulated two- to three-fold by the presence of 20 to 40 micrograms IC protein. This effect is not caused by the individual components of the IC because neither the specific Ag nor the individual antisera had any significant effect on LPL activity. With the rubella IC, a greater stimulatory effect was seen with increase in IC protein. With the influenza and diphtheria, pertussis, tetanus (DPT) IC, however, inhibition occurred when IC protein exceeded the amount of protein used for the LPL assay. C did not appear to be involved because IC prepared with heated antisera had similar effects. When intact rat epididymal fat pads were exposed to the rubella, influenza, or DPT IC, LPL activity recovered in the suspension medium was increased in each instance compared with pads exposed to a comparable amount of albumin. These findings may have implications for specific lipid changes that may occur during the immediate post-infectious period following rubella, influenza, or infections with the several bacteria whose Ag were present in the DPT IC used in these studies.
Singh
A
A
Department of Pediatrics, University of Tennessee, Memphis 38163.
Kang
E S
ES
Greenhaw
J
J
Dorsett
P
P
D000273:Adipose Tissue / Q000201:enzymology* / Q000276:immunology; D000818:Animals; D000936:Antigen-Antibody Complex / Q000502:physiology*; D004168:Diphtheria Toxoid / Q000494:pharmacology; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D004338:Drug Combinations / Q000494:pharmacology; D004822:Epididymis / Q000201:enzymology; D005260:Female; D006493:Heparin / Q000494:pharmacology; D007106:Immune Sera / Q000494:pharmacology; D009980:Influenza A virus / Q000276:immunology; D008071:Lipoprotein Lipase / Q000276:immunology*; D008297:Male; D010567:Pertussis Vaccine / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D012412:Rubella virus / Q000276:immunology; D013745:Tetanus Toxoid / Q000494:pharmacology
D000936:Antigen-Antibody Complex; D004168:Diphtheria Toxoid; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D004338:Drug Combinations; D007106:Immune Sera; D010567:Pertussis Vaccine; D013745:Tetanus Toxoid; D006493:Heparin; D008071:Lipoprotein Lipase