Bernice Schacter

Impaired cell-mediated immunity in patients with classic hemophilia

THREE cases of Pneumocystis carinii pneumonia, two of which were fatal, have recently been observed in patients with severe classic hemophilia who had been treated with lyophilized preparations of ...

Transferrin and HLA: Spontaneous Abortion, Neural Tube Defects, and Natural Selection

We report evidence that transferrin C3, a gene present in 9 to 10 per cent of whites, is associated with recurrent spontaneous abortion (P = 0.001) and that maternal transferrin genotype has an effect on the transmission ratio of the common transferrin genes (C1, C2, and C3) from heterozygous fathers to normal offspring (P less than 0.002). The effect of maternal genotype on paternal gene transmission is an unusual example of the operation of selection in the human reproductive process. This effect, together with the separate evidence for association of the transferrin C3 allele with spontaneous abortion, indicates that transferrin is a second marker (in addition to HLA) of genes important in reproduction. On the basis of comparison of the frequencies of transferrin (chromosome 3) and HLA (chromosome 6) mating types in 348 control couples and in 81 couples who had had a child with a neural tube defect, we hypothesize that some combinations of maternal and fetal genes on these two chromosomes may be associated with neural tube defects.

Inhibition of postbinding target cell lysis and of lymphokine-induced enhancement of human natural killer cell activity by in vitro exposure to ultraviolet B radiation

In vitro exposure of human peripheral blood mononuclear cells (PBMC) to ultraviolet B (uvB) radiation has been shown to inhibit natural killer (NK) cell-mediated cytotoxicity in a dose-dependent fashion. The purpose of this study was to examine the manner by which uvB produced these deleterious effects. Inhibition of NK activity was not due to lethal injury to NK cells since the viability of cell populations enriched for NK activity was greater than 90% with the uvB doses employed. uvB appeared to directly affect NK cells since procedures which removed suppressor mechanisms, such as removal of monocytes and pharmacologic inhibition of the cyclooxygenase pathway, failed to reverse the response. Furthermore, no suppression of activity of unirradiated NK cells could be produced by coincubation of unirradiated NK cells with uv-irradiated NK cells. When the single cell assay for binding and killing was employed to determine at which stage in the lytic sequence inhibition occurred, it was found that binding was normal but lysis of bound targets and the recycling capacity of active NK cells were markedly reduced. At uvB doses above 50 J/m2, both interferon alpha (IFN-alpha) and interleukin 2 (IL-2) were ineffective in augmenting NK cell-mediated cytotoxic reactions after cells had been irradiated with uvB. Furthermore, incubation of NK cells with IFN-alpha prior to irradiation failed to protect against the inhibitory effects. These studies provide evidence that in vitro exposure of NK cells to uvB radiation inhibits their function by a direct nonlethal effect and that this inhibition occurs selectively at the postbinding stage of target cell lysis.

Natural cytotoxicity in immunodeficiency diseases: Preservation of natural killer activity and the in vivo appearance of radioresistant killing

We studied spontaneous natural killer (NK) cell activity and radiation-resistant NK mediated cytotoxicity in four patients with clinically documented severe combined immune deficiency disease (SCID), and in one subject each with intestinal lymphangiectasia and cartilage-hair hypoplasia. We observed the preservation of spontaneous NK activity in all patients despite the presence of profound B- and T-lymphocytopenia and clinical immunodeficiency. NK activity was associated with relatively normal circulating numbers of OKM1+ lymphocytes, a population known to contain NK effectors. Spontaneous NK activity resistant to 3000 rad was increased in all patients, indicating the presence of activated natural killer cells in vivo. The concept of a chronically activated immune system in these patients was further supported by the presence of increased Ia positive T cells in all subjects tested, suggesting that radioresistant NK activity may be a useful parameter to measure when assessing in vivo immune activation. Our data, as well as that of others, supports the hypothesis that at least one population of NK cells is a distinct lineage arising at the differentiation level of myeloid and lymphoid stem cells in the bone marrow.

Impaired culture generated cytotoxicity with preservation of spontaneous natural killer-cell activity in cartilage-hair hypoplasia.

Recent studies of cartilage-hair hypoplasia (CHH), a form of short-limbed dwarfism, have shown that all affected individuals have a cellular proliferation defect that results in a cellular immunodeficiency. However, only a minority of CHH individuals suffer from severe, life-threatening infections. For this reason, relevant immune defense mechanisms that may be responsible for maintaining intact host defenses in the majority of CHH individuals were studied. Spontaneous and allogeneic culture-induced (mixed lymphocyte response-MLR) specific and nonspecific (NK-like) cytotoxic mechanisms were analyzed and correlated with lymphocyte subpopulations present in CHH and normal individuals. Spontaneous natural-killer (NK) activity was present at or above normal levels, but culture-induced specific cytotoxicity and NK-like cytotoxicity as well as NK-like activity by T cell lines were significantly reduced in CHH individuals. The generation of radiation-resistant cytotoxicity, which normally occurs during allogeneic MLR, was markedly diminished in CHH, and was correlated with the decreased proliferation observed in CHH cultures. Preservation of spontaneous NK activity and loss of all forms of culture-induced cytotoxicity was associated with an increase in the proportion of lymphocytes bearing a thymic independent NK phenotype (OKM1+ OKT3- Fc gamma + low-affinity E+), and a significant decrease in thymic derived OKT3+ cytolytic T cell sub-populations in CHH individuals. Therefore, an intact cellular cytotoxic effector mechanism has been identified in CHH (i.e., NK activity). Natural cytotoxicity may be of importance in maintaining host resistance to viral infections despite diminished thymic-derived effector mechanisms in cartilage-hair hypoplasia.

Antibody Response to Pneumococcal Polysaccharides in Insulin-dependent Diabetes Mellitus

Twenty-one insulin-dependent diabetics and 11 healthy control children were immunized with polyvalent pneumococcal polysaccharide vaccine. Serum antibody to pneumococcal polysaccharides was measured by radioimmunoassay before and after immunization. Although there were some differences in type-specific antibody concentrations between diabetic and control subjects, the overall antibody concentrations preimmunization, 3–4 wk postimmunization, and 6–7 wk postimmunization were similar in both populations. In both groups antibody response to immunization correlated strongly with preimmunization antibody concentration. Among the diabetic subjects there was no correlation between antibody responses and duration of disease, insulin dose, or concentration of glycosylated hemoglobin. Insulin-dependent diabetic subjects have a serum antibody response to pneumococcal polysaccharides equivalent to that of controls, and in both populations the magnitude of the antibody response correlates with preimmunization antibody levels.

Tuberculin response of lymphocytes from human skin test nonreactors; evidence for in vitro primary sensitization of T lymphocytes

Abstract Tuberculin-purified protein derivative (PPD) is a B-lymphocyte mitogen in a variety of experimental animals. Although peripheral blood mononuclear cells (PB MNC) from healthy human tuberculin responders consistently responded to PPD by increased incorporation of [ 3 H]thymidine, cell fractionation studies showed this to be due to T-lymphocyte rather than B-cell blastogenesis. Moreover, utilizing thymidine suicide experiments, the T-lymphocyte response could be categorized as antigenic rather than nonspecific mitogenic reactivity. Kinetic studies revealed a delayed peak of PPD-induced thymidine incorporation in PB MNC from tuberculin skin test-negative as compared to skin test-positive donors. This suggested in vitro primary sensitization of T lymphocytes to PPD, which was corroborated in experiments demonstrating tuberculin reactivity of human umbilical-cord blood lymphocytes.

Lymphocytes of persons with the acquired immunodeficiency syndrome and related conditions express reactivity with the monoclonal antibody 4D12 reflective of in vivo lymphocyte activation

We observed that lymphocytes obtained from healthy persons generally expressed infrequent reactivity with the monoclonal antibody 4D12, an antibody raised against a cell line infected by the human T-lymphotropic virus type I. As had been observed previously, persons bearing HLA-B5 cross-reactive antigens and certain other allotypes had frequent lymphocyte reactivity with 4D12. Lymphocytes obtained from persons infected by the human immunodeficiency virus were highly reactive with 4D12 as were lymphocytes obtained from persons with other viral or bacterial infections. Flow cytometric studies revealed greater 4D12 reactivity by larger lymphocytes, and in vitro studies demonstrated that lectin-stimulated lymphocytes acquired 4D12-reactive antigens. There was also a significant correlation between expression of 4D12-reactive antigens and the presence of the interleukin-2 receptor as recognized by the monoclonal antibody anti-Tac. Thus, the monoclonal antibody 4D12 recognizes a lymphocyte surface antigen frequently expressed among persons with various acute and chronic infections. This antigen is a marker of lymphocyte activation.

Radioresistance of culture-induced augmented natural killer-like activity

Human NK activity is radiosensitive under the control of X-linked genes. We have evaluated the expression of these genes in other forms of cellular cytotoxicity. The NK radioresistant and radiosensitive phenotype is expressed in ADCC. Specific cellular cytotoxicity, generated in a MLC with a radiosensitive donor as responder, was radioresistant. NK-like activity recruited from nonadherent cells of radiosensitive subjects stimulated with allogenic cells, mitogens (PHA, Con A or PWM), or recall antigens (TT or PPD) was radioresistant. The acquisition of radioresistance was relatively rapid, beginning within 24 hr after exposure to PHA, prior to detectable proliferation. Radioresistance of MLR augmented NK-like activity was maximal 3 days after initiation of the culture. MLR augmented NK-like activity was spared by the immunosuppressive polypeptide antibiotic CsA at doses up to 1 micrometer/ml. CsA did, however, reduce acquisition of radioresistance by the NK-like activity at doses above 0.01 mu gm/ml, a concentration which does not inhibit uptake of 3H-thymidine but does reduce the level of specific CML. These data suggest that mitogens and antigens, including allogeneic cells, are recruiting radioresistant NK-like activity which can be distinguished from the radiosensitive spontaneous NK activity of the cell donor. Further, in the MLR, both radiosensitive and radioresistant NK-like activity may be recruited.