Does a Th1 over Th2 dominancy really exist in the early stages of Mycobacterium avium subspecies paratuberculosis infections?

The immune response of ruminants to Johne's disease has been long associated with a cell mediated immune (CMI) response in the early stages of infection with a switch to an antibody response later as the disease manifests. This study examines the immune response in sheep to Mycobacterium avium subspecies paratuberculosis (Map) infections, specifically the antigen-specific interferon gamma (IFN-γ) and antibody responses as surrogates of T helper-1 (Th1) and Th2 immunity. The difference in IFN-γ production between paucibacillary and multibacillary diseased animals was also examined. The results show that sheep are more likely to have a combined antibody and IFN-γ response (seen in 50% of the animals) rather than a switch from an IFN-γ to antibody response (39%). Multibacillary diseased animals were found to have a decrease in functional ability to produce IFN-γ from cells stimulated with MAP-specific antigens and non-specific mitogens. This indicates that the immune responses to Map infections are more complex than thought, where both antibody and cellular immunity may play key roles in the early stages of disease manifestation or resistance. The loss of the cellular response in multibacillary animals may be an indication that the entire immune response is dysfunctional, with the cell mediated responses becoming affected first.     

Cannabinoids lead to enhanced virulence of the smallpox vaccine (vaccinia) virus

Indian hemp is used since thousands of years as herbal drug. We found that a single dose of cannabis resin was equally active as Δ9-tetrahydrocannabinol (THC) enhancing severity and duration of symptoms in vaccinia virus infected mice. Cowpox virus did not cause symptomatic disease, but some reduction of specific antibody production was observed in drug treated animals. In vitro cannabis was superior to THC alone at inhibiting mitogen stimulated proliferation of human and mouse spleen cells and peripheral blood mononuclear cells. Also resin sub-fractions other than THC, cannabidiol and cannabinol, recovered also from cigarette smoke, were found inhibitory, suggesting additional involvement of constituents other than psychoactive THC. The immunoregulatory effects must be differentiated from apoptotic effects on spleen cells and lymphocytic mouse cell lines, which were observed with resin and THC but not with cannabidiol or cannabinol. A significant contribution of cytotoxic effects seems unlikely as drug treated lymphocytes were still capable of producing cytokines after T-cell receptor-specific stimulation. Considering a recent case of unusually severe cowpox virus infection in a young drug taker these data confirm a risk of “soft drugs” for acquiring poxvirus infection or enhancing side effects of the smallpox vaccine and perhaps also other live vaccines.     

Immunological imbalance in uncomplicated chronic alcoholism

The lymphocyte response to unspecific mitogenic lectins and the frequency of the lymphocytary populations and two subpopulations (DR- and Fc gamma-positive T-cells) as well as the serum immunoglobulin levels were tested. Blood samples were drawn from 15 volunteers with chronic alcoholism, an no clinical detectable correlated diseases and from 8 healthy subjects as controls. An activation of the immune system was found, characterized by an increase of T lymphocytes, DR-positive T-cells, IgA and IgG. Aspects of this activation are discussed.     

Leukemia of T-helper lymphocytes: Clinical and functional features

Leukemia of T-lymphocytes is rare. Chronic and subacute forms of T-cell leukemia have been described including Sézary cell leukemia, T-cell leukemia of Japan, and rare cases of chronic lymphocytic leukemia, prolymphocytic leukemia and hairy cell leukemia. Several studies have analyzed the functional capacity of lymphocytes from patients with T-cell leukemias. In many cases Sézary cells appear to be “helper” T-cells which cooperate with B-lymphocytes in immunoglobulin synthesis. In contrast, lymphocytes from the Japanese form of T-cell leukemia have been reported to function as suppressor cells. We describe an unusual leukemia in a 40-year old man, whose clinical course was characterized by fever, jaundice, hepatosplenomegaly, anemia and neutropenia. Lymph node enlargement and skin infiltration were notably absent. The leukemic cells were atypical mononuclear cells with a high nuclear-cytoplasmic ratio and convoluted nuclei. Immunologic studies of these cells demonstrated them to be T-lymphocytes with receptors for sheep erythrocytes. They reacted with an anti-thymocyte serum and responded to T-cell mitogens and to alloantigens. The leukemic T-cells had helper activity and could cooperate with B-lymphocytes in pokeweed mitogen (PWM) stimulated immunoglobulin synthesis. Concanavalin-A (Con-A) inducible suppressor cell activity was absent. The clinical and immune studies suggest that this case represents a previously undescribed form of T-cell leukemia.     

Cell mediated immunity in childhood malaria

Children with malarial infection, due to P.Vivax and P.falcifarum, were tested for cell mediated immunity (CMI) by lymphocyte proliferate response to mitogens PHA (phytohaemagglutinin)and PWM (poke weed mitogen) and antigen PPD (purified protein derivative). This was done during the period of parasitemia and after treatment, and compared to 19 normal matched controls. There was no significant difference between the patients and the control group with regard to PHA (patients 57.4 ±50.5; controls 61.3 ±54.9); PWM (patients 27.4 ±19.9, controls 29.9 ±24.5); PPD (patients 2.2 ±1.2, controls 1.9 ±1.4). There was also no significant difference in the lymphocyte responses during the period of parasitemia and after treatment. Hence, there does not seem to be any depression of CMI as shown by lymphocyte proliferative responses during childhood malaria.     

Functions of T cells and recruitment of cellular response afterin vitro mitogenic stimulation of lymphocytes in chronic lymphocytic leukaemia

Summary In vitro stimulation of peripheral blood lymphocytes from ten patients with chronic lymphocytic leukaemia (CLL) was investigated under various culture conditions. It was confirmed that the mitogenic reactivity of whole cell populations (PBL) was delayed and depressed. When CLL rosette-forming cells (RFC) were stimulated, their³H-thymidine uptake was increased, but the pattern of the response was similar to that of whole PBL, thus suggesting some impairment of these cells. Furthermore, in order to evaluate the possible recruitment of B cells, generally thought to be unresponsive, some co-culture experiments were performed in which 10⁴ normal lymphocytes and 10⁵ CLL whole PBL or RFC-depleted cell populations were stimulated with mitogens. An amplified response of the CLL lymphocytes was obtained in all co-cultures, and this effect was more evident when specific T cell stimulants were used; autologous CLL T lymphocytes, on the contrary, failed to display such a ‘synergic’ effect. These results indicate that normal lymphocytes are able to recruit a large number of CLL lymphocytes in the mitogenic response; furthermore, the fact that in co-cultures of CLL T-depleted fractions a better response was obtained with T cell mitogens suggests that the definition of CLL as a clonal expansion of unresponsive ‘B’ lymphocytes may be inadequate.     

Characterization of human umbilical cord blood lymphocyte subsets fractionated on immobilized peanut agglutinin

Human cord blood mononuclear cells from single donors were separated on minicolumns of peanut agglutinin (PNA) coupled to Sepharose beads to yield two fractions: unbound cells (PNA-, 78%) that were eluted with phosphate buffered saline, and bound cells (PNA+, 22%) eluted with 0.2 M D-galactose. The total yield was 86% and the cells were fully viable. There was no enrichment for macrophages or for surface immunoglobulin positive (B) cells in either the PNA+ or PNA- subset. Only 26% of the PNA+ lymphocytes formed rosettes with sheep red blood cells, in contrast to 53% of the PNA- lymphocytes. The response of the PNA+ cells to mitogens and allogeneic stimulation was considerably lower than that of the PNA- cells, while that of the latter was higher than the response of the unseparated cells. The average ratios of response of the PNA+ to PNA- cells were 0.25 for PHA, 0.20 for concanavalin A, 0.15 for pokeweed mitogen, and 0.15 In the mixed lymphocyte reaction. when tested with monoclonal antibodies to lymphocyte surface markers, it was found that the PNA+ fraction was depleted of mature T cells and enriched in Ia positive cells. Our data show that the low reactivity of human cord blood mononuclear cells may be ascribed to the presence of a subpopulation of lymphocytes which are immunologically immature. They also provide further evidence that in humans the PNA receptor is a marker for immature T or B lymphocytes.     

基于PIC16F877单片机的负压吸引装置的设计

目的：介绍一种基于PIC16F877单片机的负压吸引装置，给出了装置的设计流程与具体实现方法。方法：采用PWM输出控制电动机转速达到设定的负压值，通过人机界面来实现各项控制要求。结果：能迅速达到设定值。结论：该装置实现了人机交互控制，满足各项要求。