Nonimmune lymphocyte-macrophage interaction. I. Quantification by an automated colorimetric assay

Previous studies have demonstrated a spontaneous, nonimmune interaction between lymphocytes and macrophages. This paper describes an automated colorimetric assay based on the dye, rose bengal, to quantify this interaction. The procedure entails allowing lymphocytes to adhere to preformed macrophage monolayers in the wells of microplates and then staining bound lymphocytes with rose bengal. Dye uptake and the consequent number of lymphocytes bound were quantified using an automated spectrophotometer developed for reading microplates. This procedure was used to confirm and extend the basic parameters of the system. The interaction was found to be temperature dependent but the kinetics and percentage of cells binding varied with the source of lymphocytes. However, all lymphocyte populations tested, namely, mature and immature thymocytes, T and B lymphocytes, and a range of thymoma cell lines, bound to macrophages. Furthermore, all macrophage populations examined had the ability to bind lymphocytes. The interaction also showed no strain specificity and generally lacked species specificity. It is proposed that the interaction is a highly dynamic process that enables lymphocytes to scan the surface of macrophages for self and/or foreign antigens.     

Human T lymphocytes become glucocorticoid-sensitive upon immune activation

A murine model for Transfer Factor (TF) was used in an attempt to identify the nature of its antigen-specific component. TF was prepared from lymph node cells of CBA/Ca/T6 mice sensitized 30 days previously with 2,4-dinitrofluorobenzene (DNFB). To assay for the specific component of TF, 2 × 10⁷ lymphocyte equivalents were injected intravenously into normal syngeneic recipients. Lymph node cells obtained 18–24 hr later gave a positive response in the macrophage migration inhibition (MMI) test in the presence of the soluble analog of DNFB (sodium 2,4-dinitrobenzenesulfonate). The activity of TF was abrogated by absorption with anti-Ia sera including both an Ia alloantiserum (A.TH anti-A.TL) and a xenogeneic rabbit anti-serum which exclusively recognizes carbohydrate-defined Ia antigens. Analysis by paper chromatography using the technique for purification of carbohydrate-defined Ia antigens revealed that MIF production was obtained exclusively with those fractions known to contain Ia antigenic activity. In addition, pretreatment of TF with insoluble conconavalin A (Con A) which has an affinity for carbohydrate-defined Ia antigens resulted in removal of its activity. Taken together these findings pointed to the presence in TF of I-region gene products. Absorption with antibody directed against the dinitrophenyl determinant abolished the capacity of TF to stimulate macrophage inhibition factor production suggesting that it might also contain antigen fragments possibly in association with Ia. No evidence was, however, obtained for H-2 restriction of the action of TF in vivo since it was found to exert an effect in a variety of strain combinations including A.TH and Balb/c which share no known common I-region specificities. Parallel experiments were carried out with the lymphocyte transformation assay since this is known to be a measure of the nonspecific components in TF. Pretreatment with mouse allo-anti-Ia^k serum directed against both protein-and carbohydrate-defined Ia antigens caused a partial reduction in the proliferative response. In contrast no change in response was observed when the TF was absorbed with insoluble Con A or anti-DNP serum. Furthermore, lymphocyte transformation was obtained with only one of the three paper chromatography fractions positive in the MMI assay as well as two other different fractions. Taken together, these findings permitted a distinction to be made between specific and nonspecific components of TF and indicated that the specificity of TF could be explained in terms of the presence of I-region gene coded products possibly in association with antigen fragments.     

Interaction of phosphonium ions with Arthrobacter globiformis: evidence for the operation of an efflux system

Abstract Substrate-induced efflux of methyltriphenylphosphonium ion (MTP) from Arthrobacter globiformis has been demonstrated using organisms depleted of endogenous reserves by starvation. Further evidence for the operation of a mediated efflux system was provided by studies on the effect of analogues of MTP on MTP accumulation.     

Egg Enzymes of the Ruminant Nematode Trichostrongylus colubriformis

Summary

Preparations from eggs of the ruminant nematode Trichostrongylus colubriformis were examined for the presence of selected enzymes. Chitinase (0.12 units/mg total protein), collagenase (0.56 units/mg total protein), lipase (0.16 units/mg total protein) and acetylcholinesterase (0.61 units/mg total protein) were detected. Hatching of nematode eggs may require several forms of enzymatic activity.     

Ontogeny of the antibody-forming cell line in mice. IV. Appearance of cells bearing Fc receptors, complement receptors, and surface immunoglobulin.

The ontogeny of Ig, FcR, and CR-bearing cells in liver and spleen has been followed by using rosetting procedures. These studies demonstrated a sequential appearance of surface receptors during development. Two types of Ig+ cells could be distinguished according to their rosette morphology and adherence to carbonyl iron: 1) an adherent cell which bound few erythrocytes was found predominantly in fetal liver from 13 days gestation and 2) a nonadherent cell which bound larger numbers of erythrocytes appeared in small numbers in fetal liver from day-16 gestation but represented the major Ig+ cell type after birth. Changes in the proportions of receptor-bearing populations occurred at two particular periods during ontogeny. The first was at birth, where an increase in the proportion of FcR+ cells occurred and the proportion of type 2 Ig+ cells rose rapidly. This probably represented the first appearance of FcR+ B lymphocytes even though cells bearing FcR were detected in fetal liver of all ages (days 12 to 18). The second period was around 10 days after birth when the proportion of Ig+ cells again increased concomitant with the appearance of CR+ nonadherent cells.