I-J-positive cloned macrophages as accessory cells for the induction of suppressor T cells in vitro

Functional equivalence of cryptococcal and haptene-specific T suppressor factor (TsF). I. Picryl and oxazolone-specific TsF, which inhibit transfer of contact sensitivity, also inhibit phagocytosis by a subset of macrophages

Monoclonal and conventional cryptococcal-specific T suppressor factors (TsF) (also called TsFmp) depress phagocytosis by a subset of macrophages, while picryl- and oxazolone-specific TsF depress the passive transfer of contact sensitivity. This paper shows that these haptene-specific TsF also inhibit phagocytosis by a subset of macrophages and, using this assay, that the anti-haptene TsF resemble the anti-cryptococcal TsF in five respects: (i) the need for reexposure to specific antigen to trigger the release of TsF; (ii) genetic restriction in action; (iii) possession of an antigen-binding site; (iv) expression of I-J determinants; and (v) inactivation by reduction and alkylation. Purification of the anti-picryl TsF by sequential affinity chromatography indicates that the inhibition of phagocytosis is due to the TsF itself and not to a TsF-antigen complex. The TsF inhibits phagocytosis by a direct action as macrophages treated with TsF and exposed to antigen do not release a second factor which inhibits phagocytosis. These results and those of the accompanying paper indicate that the anti-cryptococcal and anti-haptene TsF are functionally equivalent, antigen-specific suppressor factors.

Persistent infection with herpes simplex virus type 1 in an Ia antigen-positive murine macrophage cell line

The interaction of herpes simplex virus type 1 (HSV-1) with murine macrophage cell lines was examined. The cell lines appeared to be moderately permissive for HSV-1 replication, though the yield of the virus was limited compared with that in Vero cells. Furthermore, the murine macrophage cell line SL-1, bearing Ia antigen, was persistently infected with HSV-1 for over one year, and was designated SL-1/KOS. Persistent infection could not be established in an Ia antigen-negative macrophage cell line, SL-4. In the SL-1/KOS culture, there was a small number of infected cells as revealed by infectious center assay. Treatment with monoclonal antibody against HSV-1 cured the persistent infection. Therefore maintenance of the persistent infection is considered to be due to a carrier culture consisting of a minority of infected cells and a majority of uninfected cells. In the SL-1/KOS cultures a low level of interferon (IFN) was found. When a large amount of exogenous recombinant murine IFN-beta (10(5)-10(6) international units/ml) was added to the culture, virus production diminished to undetectable levels. These results suggest that IFN plays an important role in the maintenance of persistent infection. In long-term persistently infected cultures, syncytium formation appeared and the virus from such cultures had a different DNA structure from that of the virus originally used for infection as revealed by restriction endonuclease analysis.

Visualization of anti-I-J antibody binding sites on bone marrow-derived macrophages

I-J antigens on BMDM were visualized by immunofluorescence. Nonspecific binding of IgG antibody to Fc receptors was eliminated by the pretreatment of the antibody with anti-mouse IgG Fc portion antibody.

Cell-cell interaction responsible for the induction of first order suppressor T cells in hapten-specific contact sensitivity reactions

C3H/He mice were found to be low responders in the contact sensitivity response to ABA. Intravenous injection of ABA-coupled syngeneic spleen cells induced hapten-specific Ts in C3H/He mice. These cells were Ts1 because they acted on the inductive phase of the contact sensitivity. They could suppress the contact sensitivity in H-2-compatible CBA mice which were known to be high responders to ABA. Using in vivo and in vitro systems for the induction of Ts, it was shown that I-A-I-J+Thy-1- adherent cells were necessary as APC for the induction of Ts1.