Interleukin-3 and lipopolysaccharide interact to inhibit proliferation of mouse bone marrow cells.
The mechanisms underlying the multiple biological activities presented by interleukin-3 (IL-3) are not yet fully understood. As a regulator of hematopoiesis, IL-3 is known to interact with several other molecules. The present study investigates the interaction of IL-3 and Escherichia coli lipopolysaccharide (LPS), which results in the inhibition of the in vitro proliferation of mouse bone marrow (BM) cells. BM cells from adult BALB/c mice were cultured at 37 degrees C, with 5% CO2 in air, in RPMI-1640 medium complemented with fetal calf serum. Viable cells were counted on day 3. Whereas IL-3 and LPS alone increased the number of viable cells as compared to control cultures, the simultaneous addition of the factors lowered that number below controls. Cell fractions of different densities, isolated by Percoll gradient (70, 50 and 40%), also behaved in the same way. The same effect was observed when BM non-adherent cells were isolated 1 day after initiation of cultures and analyzed 2 days later, but not if the culture was initiated in the absence of adherent cells. Pre-incubation experiments showed that only if total BM cells were pre-incubated for 24 h with IL-3/LPS or LPS alone was the inhibitory effect of the two factors maintained. Soluble inhibitory factors were only observed in cultures of adherent BM cells.
Silva
Z Z
ZZ
Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Furlanetto
M P
MP
Marques
E K
EK
Nardi
N B
NB
D000818:Animals; D001854:Bone Marrow Cells; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004347:Drug Interactions; D004926:Escherichia coli; D005260:Female; D006410:Hematopoiesis; D007377:Interleukin-3 / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C
D007377:Interleukin-3; D008070:Lipopolysaccharides