摘要:

P388D1, a mouse macrophagelike cell line, was adapted to grow continuously in an unsupplemented, serum‐free culture medium and continued to elaborate substances that were mitogenic for quiescent mouse fibroblasts (BALB/c 3T3 cells) and for thymocytes suboptimally stimulated with lectins. We have previously described [37] the fibroblast mitogenic activity as a macrophage‐derived competence factor (MDCF). Serum‐free, macrophage‐conditioned culture medium was concentrated 1,000‐fold by a combination of ultrafiltration (hollow fiber) and lyophilization. Concentrates of medium were subjected to gel filtration (Sephadex G‐75 or G‐150), and the fractions were assayed for mitogenic activity (MDCF) on density‐arrested BALB/c 3T3 cells and for Interleukin‐1 (IL‐1) activity in suboptimally stimulated (Con A) mouse thymocytes. The apparent molecular weight (MW) of MDCF activity was estimated at 56,000 daltons, whereas the peak of IL‐1 chromatographed at an apparent MW of 14–16K daltons. There was no detectable IL‐1 activity in the MDCF fractions and no detectable MDCF in the IL‐1 fractions. These data indicate that P388D1cells produce both MDCF and IL‐1 activities under continuous serum‐free conditions and that the two activities are not identical. Stimulation of responsive mononuclear phagocytes with lipopolysaccharide and/or lymphokine‐rich supernates resulted in a differential modulation of MDCF and IL‐1 activities. Finally, antibody‐purified IL‐1 had no significant ability to stimulate DNA synthesis in quiescent fibroblasts at concentrations that were mitogenic for thymocytes. However, IL‐1 did augment the mitogenic activity of suboptimal amounts of platelet‐derived growth factor (PDGF), another competence factor. Further studies revealed that neither the generation nor the activity of MDCF was modulated by the presence of various inhibitors of proteolytic enzymes.

ISSN:0741-5400    

DOI:10.1002/jlb.35.1.115

出版商:Wiley    

年代:1984

数据来源: WILEY

摘要:

Six IgG monoclonal antibodies representing the four murine IgG isotypes were active individually in ADCC to T‐lymphoma targets mediated by murine macrophages and human blood K cells. The monoclonals were directed against four antigens (Thy‐1.2, H‐2k, Ly 2.1, Ly 9.2). None was as effective in ADCC as allo‐anti‐Thy‐1.2 serum or rabbit anti‐mouse spleen serum, even at plateau levels of killing. Monoclonals gave the highest levels of ADCC at relatively low amounts of antibody bound to targets; increasing the amount of bound antibody by 10‐ to 100‐fold did not increase murine macrophage‐mediated cytotoxicity. In contrast, ADCC using alloantiserum continued to increase over the same range of antibody bound to the tumor targets. The activity of individual monoclonals was not enhanced by the presence of various dilutions of normal mouse or rabbit serum, suggesting that the superiority of the allo‐ and heteroantisera was due to their content of heterogeneous antibodies. IgG monoclonls of different isotypes and recognizing different antigens gave enhanced ADCC in combination; monoclonals to the same antigen did not. An IgM anti‐Thy‐1.2 monoclonal was inactive in ADCC and inhibited the activity of IgG monoclonals of the same specificity. These studies show that IgG antibodies of different specificity and class can collaborate in ADCC, and that this cooperative effect is not due simply to increased amounts of antibody bound to the tumor targets.

ISSN:0741-5400    

DOI:10.1002/jlb.35.1.131

出版商:Wiley    

年代:1984

数据来源: WILEY

ISSN:0741-5400    

DOI:10.1002/jlb.35.1.141

出版商:Wiley    

年代:1984

数据来源: WILEY