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Biomedical subjects

G Fernandes

Publications and source records attributed to G Fernandes.

At least 127 records · Page 7Linked to original sources
PubMed1981

Spontaneous and antibody-dependent cellular cytotoxicity by lymphocyte subpopulations in peripheral blood and spleen from adult untreated patients with Hodgkin's disease.

Subpopulations of lymphocytes in the peripheral blood and spleen from adult untreated patients with Hodgkin's disease were studied for spontaneous (SCMC) and antibody-dependent cellular cytotoxicities (ADCC). Peripheral blood from seven of 24 patients demonstrated abnormally low T cell-mediated SCMC when compared to age- and sex-matched healthy controls. Only two of these patients also demonstrated low T cell ADCC and non-T cell-mediated SCMC and ADCC. T cell ADCC in the peripheral blood of patients with involved spleen was significantly higher (P less than 0.05) when compared to those in whom spleen was not involved. When SCMC and ADCC were compared between peripheral blood and splenic lymphocytes with regard to involvement of spleen by Hodgkin's disease, non-T cell SCMC in the involved spleen was significantly lower (P less than 0.05) than their peripheral blood non-T cell SCMC. SCMC and ADCC tended to be higher in patients with stages III and IV of Hodgkin's disease when compared to those with stages I and II. However, the differences were not statistically significant. No direct relationship was observed between T and SCMC or ADCC and the proportion of T cells with IgG Fc receptors (T gamma). The significance of these observations is discussed.

Adult↗
PubMed1981

Mechanism of NK cell activation: relationship between Qa5+ NK cells and lymphocytes.

Interferon (IF) induces within 20 hr of incubation Qa5+Thy-1- NK cells but Qa5-Thy-1+ cytotoxic cells in cultures of murine splenocytes. The mechanism of Qa5+ NK cell activation has been studied by using tumor necrosis serum (TNS), concanavalin A (Con A), and lipolysaccharide (LPS) as additional NK cell-inducing reagents. It was found that IF and TNS activate precursor NK cells directly without the involvement of accessory cells. The T cell mitogen Con A and the B cell mitogen LPS, on the other hand, induced Qa5+ NK cells only in the presence of lymphocytes. Con A-stimulated T cells and LPS-stimulated B cells release factors into the culture medium that activate Qa5+ NK cells. Since Con A and LPS are known to be interferon inducers, it is inferred that Con A-induced and LPS-induced activation of NK cells is mediated by IF. The data demonstrate that NK cells become activated as a consequence of lymphocyte activation and thus suggest a relationship between lymphocyte dependent- and NK cell-dependent defense systems. This relationship is also implied by observations made with NZB mice. NZB mice lose NK cell activity at the time when they develop autoimmune diseases.

Animals↗
PubMed1980

The effect of diet on autogenous immunity to mouse mammary tumor virus in C3H/Bi mice.

Antibody levels to mouse mammary tumor virus (MuMTV) in sera of C3H/Bi, C57BL/6 and AKR mice were assayed by an enzyme-linked immunosorbent assay (ELISA). It was found that antibody levels to MuMTV were highest in sera of C3H/Bi females which have a high incidence of breast cancer and low in male C3H/Bi and female C3H/Bi foster-nursed on C57BL/6 females. Sera of C57BL/6 and AKR mice showed very low or undetectable levels of antibody to MuMTV. Reduction of caloric intake sufficient to inhibit mammary tumor formation strikingly inhibited formation of antibody against MuMTV. The lowest levels of antibody were observed in sera of mice fed 10 cal/day of a defined diet. Significantly higher levels developed in the sera of mice fed 16 cal/day of the same defined diet. The highest antibody levels against MuMTV, however, were seen in sera of mice fed lab chow ad libitum but no correlation was evident between levels of antibody and tumor size. These studies indicate that dietary caloric restriction has a profound influence on the development of both mammary adenocarcinoma and antibody responses to MuMTV.

Age Factors↗
PubMed1980

Humoral and cell-mediated immune responses in fully allogeneic bone marrow chimera in mice.

AKR mice were protected from lethal irradiation and established as long-lived chimeras by transplanting allogeneic C57BL/6 (B6) bone marrow that had been treated in vitro with anti-Thy-1 antiserum without complement. In these chimeras, which were designated [B6 {arrow} AKR], virtually all the thymus and spleen cells were shown to be derived from the B6 donor; several immune functions studied in these chimeras were as follows: (a) The chimeric mice were tolerant of histocompatibility antigens of both donor and recipient strain and nearly fully reactive to antigens of third party, as revealed by Simonsen's splenomegaly assay. The tolerance of these chimeras could not be attributed to suppressor cells but was compatible with clonal depletion. (b) Proliferative responses to concanavalin A, phytohemagglutinin, and lipopolysaccharide as well as natural killer and antibody-dependent cell- mediated cytotoxicity activity of the chimeric mice was normal. (c) Plaque- forming cell (PFC) assays of antibody responses to sheep erythrocytes (SRBC) showed gross deficiency in the primary response of the [B6 {arrow} AKR] and [AKR {arrow} B6] chimeras. By contrast, [B6-H-2(k)(E(k)) {arrow} AKR] H-2-compatible chimeras and [AKR {arrow} AKR] syngeneic marrow transplanted mice had normal primary PFC responses. PFC responses after secondary stimulation with SRBC, however, revealed vigorous direct plaque formation and substantial but somewhat smaller indirect plaque formation in the [B6 {arrow} AKR] chimeras. This observation favors operationally the concept of adaptive differentiation proposed by Katz et al. (44). (d) Analysis of ability of the chimeras to develop and express delayed-type hypersensitivity responses to contact sensitizer (2,4-dinitro-l-fluorobenzene [DNFB]) showed no apparent immunodeficiency of either chimeras to this form of immunization. Development of immunologic tolerance to DNFB, however, was grossly deficient in [B6 {arrow} AKR] chimeras but normal in [AKR {arrow} AKR], [B6 {arrow} B6], and [E(k) {arrow} AKR] chimeras. These findings indicate that full chimeras across major histocompatibility complex have considerable immunologic vigor even though primary immune responses that require histocompatibility between interacting cell types are initially defective.

Animals↗
PubMed1980

Immune and autoimmune aspects of diabetes mellitus.

The immune and autoimmune aspects of diabetes mellitus are reviewed. Emphasis is given to the clinical association of diabetes with other autoimmune disease; the increased incidence of organ-specific autoimmunity in diabetic patients; the occurrence of humoral and cell-mediated antipancreas (islet) autoimmunity in diabetes; the association of HLA with juvenile-onset, insulin-dependent diabetes mellitus and with certain specific subpopulations of diabetic patients; the possible role of viruses in the etiology of diabetes; and the occurrence of alterations in humoral and cell-mediated immunity, granulocyte function, and the host defense against infectious agents in human diabetics and in animals with experimental diabetes.

Animals↗
PubMed1980

Neuraminidase treatment of human T lymphocytes: effect on Fc receptor phenotype and function.

Purified peripheral blood T cells or T mu cells from normal healthy donors were treated in vitro with neuraminidase and examined for the expression of IgM Fc and IgG Fc receptors. Increasing concentrations of neuraminidase selectively removed IgM Fc receptors, whereas the number of T cells expressing IgG Fc receptors was significantly increased. Following neuraminidase treatment, IgM Fc receptors could be regenerated by reincubation of T cells at 37 degrees C. The regeneration of IgM Fc receptors could be blocked by treatment with cycloheximide. Neuraminidase treatment of purified T mu cells resulted in the expression of IgG Fc receptors on a subpopulation of T mu lymphocytes. A small percentage of the neuraminidase-treated T cells expressed receptors for both IgG and IgM. Treatment of T cells with neuraminidase did not effect T cell-mediated spontaneous cytotoxicity (SLMC) or antibody-dependent cellular cytotoxicity (ADCC). Our results indicate that T cell Fc receptor phenotypes can be modulated in vitro without significantly altering their functional capacity.

Cytotoxicity, Immunologic↗
PubMed1980

Nutritional modulation of immune responses.

Malnutrition has been linked in field studies with increased susceptibility to infection, often associated with severe marasmus or kwashiorkor. However, studies by Jose and colleagues revealed an apparent paradox: while B-cell immunity was decreased by chronic moderate malnutrition, several aspects of T-cell immunity were enhanced. In extensive experimental studies we have analyzed the effects of dietary restriction in immunologic function and development of disease. Our investigations may be grouped into three related areas. 1) Differential effects of protein or protein-calorie malnutrition on B-cell and T-cell immunity. While antibody-mediated immunity was impaired in animals moderately restricted with respect to protein or total calories, several T-cell functions were consistently enhanced in mice, rats, guinea pigs, and monkeys. 2) Influence of restricting a single nutritional element, the trace metal zinc, on immunologic function. Zinc deficiency produces progressive thymic involution and a progressive loss of T-cell immunity functions in mice and rats. While congenital failure to absorb this element normally is the single cause of hereditary acrodermatitis enteropathica, a frequently lethal disease both in humans and in cattle, acrodermatitis enteropathica has also been linked with common variable immunodeficiency disease, total parenteral alimentation with preparations lacking zinc, several forms of cancer, marasmus, and kwashiorkor. 3) Inhibition by dietary restriction of development of the diseases of aging. Disorganization of thymus-derived immunity, and development with aging of genetically determined diseases in several strains of mice, can be sharply curtailed or even prevented by reducing the intake of total calories or fat. Similarly, development of mammary cancer in C3H female mice is prevented by restricting dietary intake of fat.

Aging↗
PubMed1979

Impairment of cell-mediated immunity functions by dietary zinc deficiency in mice.

Several immunologic features were analyzed in mice on a zinc-deficient diet [Zn(-)], in mice pair-fed a diet containing zinc [Zn(+)], in mice fed a Zn(+) diet ad lib, and in mice fed laboratory chow ad lib. When placed on a Zn(-) diet, 6- to 8-week-old A/Jax, C57BL/Ks, and CBA/H mice showed loss of body weight, low lymphoid tissue weight, and profound involution of the thymus within 4-8 weeks after initiation of the regimen. Approximately 50% of the mice on the Zn(-) diet developed severe acrodermatitis enteropathica (lesions on tail and paws) and diarrhea. Pair-fed mice on the Zn(+) diet did not show any of these symptoms. Mice on the Zn(-) diet showed the following immune deficiencies: (i) depressed plaque-forming cells against sheep erythrocytes after in vivo immunization; (ii) depressed T killer cell activity against EL-4 tumor cells after in vivo immunization; and (iii) low natural killer cell activity. However, antibody-dependent cell-mediated cytotoxicity against chicken erythrocytes was normal in the mice on the Zn(-) diet. Deficiency of T killer cell activity was not observed when immunization with EL-4 allogeneic lymphoma cells was carried out in vitro. Progressive loss of relative and absolute number of Thy 1.2+ cells and a proportionate relative increase in cells bearing Fc receptors was seen in spleen and lymph nodes of Zn(-) animals. It appears that zinc is an essential element for maintenance of normal T cell and other immune functions in vivo.

Animals↗
PubMed1979

Abnormalities in clonable B lymphocytes and myeloid progenitors in autoimmune NZB mice.

Cloning procedures were used to study B lymphocytes and progenitors of granulocytes and macrophages in NZB mice. Numbers of B cells that were detected in sheep erythrocyte-containing semisolid cultures were only slightly elevated in NZB tissues, and these were normally sensitive to inhibition by anti-mu or anti-delta antibodies or prostaglandin E. However, NZB mice rapidly developed large numbers of B cells that could be cloned in the presence of lipopolysaccharide, and these included unusual anti-mu resistant cells. Numbers of myeloid precursors in NZB bone marrow that were responsive to colony-stimulating activity in L-cell conditioned medium or endotoxin serum were at least normal, but at all ages granulocyte-macrophage precursors were poor responders in cultures stimulated by WEHI-3 cell conditioned medium. Almost no colonies were elicited in NZB cultures with a colony-stimulating activity moiety from WEHI-3 cells. Prostaglandin sensitivity of myeloid precursors from NZB and CBA mice was also different. Codominant genetic control of these abnormalities was suggested by their partial expression in F1 hybrid NZB X CBA and NZB X NZW mice. NZB mice expressed an unexpected IgD allotype allele.

Animals↗
PubMed1979

Studies in acute leukemia. I. Antibody-dependent and spontaneous cellular cytotoxicity by leukemic blasts from patients with acute nonlymphoid leukemia.

Leukemic blasts from patients with acute nonlymphoid leukemia were examined for the presence of Ig, receptors for IgGFc, and for their capacity to mediate antibody-dependent cellular cytotoxicity (ADCC) against chicken red blood cells (RBC) coated with IgG and spontaneous cell-mediated cytotoxicity (SCMC) against cells of K562 cell line. Leukemic blasts from acute myeloblastic leukemia (AML) patients lacked both Fc receptors and Ig on their surface, had no SCMC activity and majority, but not all of them, lacked ADCC activity. Leukemic blasts from patients with acute monocytic leukemia (AMOL) had Fc receptors, and 50% had IgG on their surface. IgG was cytophilic and appeared not to be directed against cell-surface antigens. This antibody did not interfere with the ADCC activity of leukemic cells. Leukemic blasts from majority of patients with AMOL mediated ADCC, but had no SCMC activity. An association between ADCC and presence of Fc receptor was observed.

Adult↗