Candace C. McCombs

Cellular interactions in lymphocyte proliferation: Effect of syngeneic and xenogeneic macrophages☆

Abstract The interaction of syngeneic and xenogeneic macrophages with purified lymphocytes from human peripheral blood or mouse spleen was examined in the in vitro proliferative response to phytohemagglutinin (PHA) and allogeneic cells. Both syngeneic and xenogeneic macrophages markedly augmented the response of lymphocytes to suboptimal mitogen concentrations. Kinetic studies indicated that the effect of the macrophages was to increase the number of lymphocytes proliferating in response to mitogen. Human macrophages were also able to support a proliferative response to allogeneic cells by purified mouse lymphocytes. These results indicate that the possible histocompatibility requirement between lymphocyte and macrophage necessary for proliferation induced by soluble antigen is not a requirement for the proliferative response to mitogen and alloantigen.

Reversible melphalan-induced lung damage

Pulmonary toxicity occurs after the administration of several different chemotherapeutic agents. Pulmonary toxicity due to melphalan alone has not been documented. In the patient we describe respiratory symptoms and pulmonary infiltrates developed twice within two weeks of the second course of a monthly melphalan and prednisone regimen. Open lung biopsy revealed interstitial pneumonitis. The infiltrates cleared on both occasions when melphalan was withheld. Special studies performed seven weeks after the last dose of melphalan had been given revealed that the patients alveolar macrophages suppressed phytohemagglutinin induced blastogenesis of his peripheral lymphocytes. Melphalan itself did not stimulate the blastogenesis of the peripheral lymphocytes. Melphalan should be added to the list of therapeutic agents that induce pulmonary disease. However, the pathogenesis of the disease remains to be elucidated.

HLA-Bw44 and HLA-DRw4 in male Sjögren's syndrome patients with associated rheumatoid arthritis☆

We identified HLA-A, B, and DR antigens in 16 predominatly male Caucasian patients with Sjogrens syndrome and associated rheumatoid arthritis (SS-RA). These patients had an increased prevalence of both HLA-Bw44 and HLA-DRw4. HLA-Bw44 was detected in 50% of the patients and only 26% of 172 control subjects. HLA-DRw4 (an antigen previously shown to be associated with RA) was found in 57% of the patients and 30% of controls (P < 0.04). The most striking finding was the occurrence of both of these antigens together in the same patients (716, P < 0.04 after correction for the number of antigens tested). In addition, our data confirmed the absence of an association of SS-RA with either HLA-B8 or HLA-DRw3, in contrast to the previously reported increase of these antigens in Sjogrens syndrome patients without an associated connective tissue disease (SS). A comparison of our results with previous studies suggests that SS-RA is genetically distinct from SS and may be different from RA without Sjogrens syndrome.

Surface properties of lymphocyte subpopulations in autoimmune NZB/NZW F1 hybrid mice: Alterations correlated with the immunodeficiency of aging

Partitioning in a two-polymer aqueous phase system was used to probe the surface properties of lymphoid cell subpopulations in aged male NZB/NZW F1 hybrid (B/W) mice, an important model of autoimmunity, immunodeficiency, and lymphoid malignancy. Spleen cells were fractionated by countercurrent distribution (CCD, a multiple-step extraction procedure) in a charged dextran-polyethylene glycol system. CCD of spleen cells from young, clinically normal male B/W mice yielded several broad distribution patterns which frequently had two or more peaks. Analysis of differentiation antigens and functional properties of cells from different parts of the distribution revealed a subfractionation of the three major lymphocyte subpopulations. B lymphocytes had a low partition coefficient (K); T cells had an intermediate K and null cells had the highest K. To examine the partitioning behavior of T lymphocytes, spleen cells which were nonadherent to nylon wool columns were subjected to CCD. Nonadherent cells from young B/W mice consistently gave a single peak with high K. Aged mice (18 months) usually had nonadherent cells with a predominantly low K. In some experiments a systematic increase in the number of these cells could be demonstrated with increasing mouse age. An analysis of the adherence and partitioning behavior of lymphocyte subpopulations revealed no change in the adherence properties or proportions of B lymphocytes in aged mice. The large proportion of cells having a low partition coefficient in the nonadherent spleen cell population of old mice appears to be due to an increase in the number of null cells and in a decrease in the K of some T lymphocytes.

The cellular basis of accelerated human lymphocyte activation following preliminary culture: The role of T lymphoblasts☆

Abstract When human peripheral blood mononuclear cells are precultured, they demonstrate greatly accelerated responses to mitogens and alloantigens. This increased responsiveness, termed cultural augmentation, was investigated to help elucidate the process of lymphocyte activation. The cellular basis of accelerated reactivity was studied by determining the capacity of purified lymphocytes to undergo cultural augmentation after depletion of monocytes. Lymphocyte preparations with less than 0.2% monocyte contamination demonstrated augmentation after preliminary culture comparable to that of mononuclear cells containing 15–25% monocytes. After preculture, preparations of purified lymphocytes contained 5–15% very large cells (three times the diameter of uncultured lymphocytes). When fractions enriched or depleted with respect to these large cells were obtained by velocity sedimentation at unit gravity, the degree of cultural augmentation was found to correlate with the percentage of large cells present. Morphologically the large cells appear to be lymphoblasts. They lack esterase or peroxidase staining granules, do not ingest latex particles, and do not have IgM or IgD on their surface. A majority of the large cells form spontaneous rosettes with sheep red blood cells indicating they are T lymphoblasts. The cells responsible for cultural augmentation had recently synthesized DNA, further suggesting a crucial role of the lymphoblasts; BUDR treatment 2 days before the end of preliminary culture, followed by light prior to culture with mitogen, ablated most of the augmented response.