Recombinant interleukin-4-treated macrophages, epithelioid cell surrogates, harbor and arrest Mycobacterium avium multiplication in vitro.
Our group has previously described that murine peritoneal macrophages treated in vitro for 7 days with recombinant interleukin-4 (rIL-4) acquire morphological and functional characteristics of epithelioid cells (ECs) found in granulomatous lesions. Although EC function has not been clarified so far, it has been suggested that these cells could present antigens and control multiplication of mycobacteria. These aspects have been addressed here using in vitro EC surrogates. Using immunocytochemistry and immunofluorescence methods, we have observed an increased expression of CD11b, CD54, CD86 and CD40 molecules on rIL-4-treated macrophages when compared to untreated ones. Cytokine-treated cells were less phagocytic for latex beads (P<0.03) and more pinocytic for dextran particles than untreated macrophages. T-cell lymphoproliferation assays using ovalbumin (OVA) and Mycobacterium avium as antigens showed that both cultured macrophages were equally efficient as antigen presenting cells (APCs). However, M. avium antigens were better presented in vivo by EC surrogates (P<0.01). Both macrophage cultures were similarly infected by M. avium. However, while the infection level was maintained in the cytokine-treated population, untreated macrophages showed a progressive increase in the number of bacilli/cell with time (P<0.01) and a reduction of about 65% in cell population. After 96 h of M. avium infection, untreated cells secreted higher amounts of tumor necrosis factor-alpha (P<0.005) while rIL-4-treated macrophages showed higher, although not significant, transforming growth factor-beta production. Also, EC surrogates produced less nitric oxide than control macrophages (P<0.05). Hence, EC surrogates restrain M. avium growth and act as APCs in vitro and in vivo.
Chinen
Ludmilla T D
LT
Discipline of Immunology, Department of Microbiology, Immunology and Parasitology, Federal University of São Paulo, Rua Botucatu 862, 4th andar, Vila Clementino, 04023-900 São Paulo, Brazil.
Cipriano
Ivone M
IM
de Oliveira
Rosângela S
RS
Leão
Sylvia C
SC
Mariano
Mario
M
Carneiro
Célia R Whitaker
CR
D000818:Animals; D051940:B7-2 Antigen / Q000096:biosynthesis; D039481:CD11b Antigen / Q000096:biosynthesis; D019013:CD40 Antigens / Q000096:biosynthesis; D002478:Cells, Cultured; D003911:Dextrans; D015622:Epithelioid Cells / Q000276:immunology / Q000382:microbiology*; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000494:pharmacology; D008233:Lymphotoxin-alpha / Q000096:biosynthesis; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000382:microbiology*; D008297:Male; D051379:Mice; D008863:Microspheres; D009162:Mycobacterium avium / Q000254:growth & development*; D009569:Nitric Oxide / Q000096:biosynthesis; D010587:Phagocytosis; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D051940:B7-2 Antigen; D039481:CD11b Antigen; D019013:CD40 Antigens; D003911:Dextrans; D008233:Lymphotoxin-alpha; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D015847:Interleukin-4; D009569:Nitric Oxide