Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The kinetics of various specific and nonspecific immunologic responses were examined in BALB/c mice infected with 17X nonlethal Plasmodium berghei yoelii (a self-limiting infection). The sequence of events after infection was characterized by rapid sensitization of splenic T cells to malaria antigen and polyclonal B cell activation, followed by a period of depressed splenic proliferative responses in vitro to mitogens (PHA and LPS) and malaria (specific) antigen. At the same time, suppressed primary in vitro splenic PFC responses to trinitrophenyl-aminoethylcarbamylmethyl-Ficoll (TNP-F) were seen. This suppression was an active process requiring adherent cells. During this period, levels of antimalarial antibody also increased exponentially. As the infection was cleared, splenic malaria antigen-specific proliferative responses were again observed and splenic PFC and in vitro mitogen responses returned to preinfection levels after variable periods of time. Both splenic proliferative responses to malaria antigen and antimalarial antibody responses remained persistently elevated. In addition, some responses were examined in mice infected with 17X lethal P.b. yoelii (a fatal infection); in comparison to the early responses of mice infected with the nonlethal substrain, there was a decrease and delay in the development of a splenic T cell response to malaria antigen and a blunted antimalarial antibody response.
 ...
PMID:Immunity to Plasmodium berghei yoelii in mice. II. Specific and nonspecific cellular and humoral responses during the course of infection. 7 10

6 commercially available ELISA kits and 4 new Brazilian made methods for detecting HIV were compared on 2 panels of sera, 292 from AIDS patients, HIV-positives and negatives, and 180 sera from asymptomatic blood donors, including 90 HIV-positives. The kits tested were 5 ELISAs: Roche Diagnostica (Basel), Hoechst Enzygnostic (Sao Paulo), Virgo Electronuclionics (Columbia MD), Organon Teknika (Boxtel, Netherlands), Salck Industria e Comercio de Produtos Biologicos (Sao Paulo), and a passive hemagglutination test, (Salck Ind), and indirect immunofluorescence IIF (Virgo electronucleonics, Columbia), a dot blot (Embrabio, Empressa Brasiliera de Biotecnologia Ltda, Sao Paolo) and Karpas AIDS cell test, Fujichemical Industries Ltd (Chokeiji, Takaoka, Japan). The sensitivities ranged from 84.2% to 100% with no significant differences in sera from panel A. In panel B, the sensitivity of the PHA test was significantly lower than that of the ELISA and the AIDS cell tests. The specificities of the PHA and the AIDS cell tests were also lower than that of the ELISA. The costs of all the tests were similar, but the equipment needs varied. The simplest tests to perform were the dot blot assay, PHA and Karpas AIDS cell test. The Hoechst ELISA is simpler because it does not require dilution of the serum. The dot takes too long for use in a blood bank, 16-18 hours. Immunofluorescence tests would be practical in countries already screening blood for malaria or Changes disease. Brazil is not doing so on a large scale due to lack of political will. In countries with high incidence of malaria, Chagas disease, leishmania, hepatitis and leprosy, HIV test need to be tested on local sera because of possible B cell activation.
 ...
PMID:Evaluation of enzyme-linked immunosorbent and alternative assays for detection of HIV antibodies using panels of Brazilian sera. 209 32

The effect of primaquine on the cellular immune responses (lymphocyte subpopulations and their proliferative responses with PHA, Con-A and LPS, and phagocytosis by monocytes) of normal rhesus monkeys was studied under both in-vivo and in-vitro conditions. When the lymphocytes and monocytes from normal animals were treated in-vitro with primaquine, at concentration normally attainable during therapy, a significant inhibition in blastogenic response of lymphocytes and phagocytic capacity of monocytes was noticed after 4 hours of treatment. In contrast, the in-vivo effect of primaquine treatment on these cells was innocuous. From this study it is clear that the primaquine does not act as an immunosuppresant and can be given safely to any type of malaria patient.
 ...
PMID:Primaquine: its effect on cellular immune response of normal rhesus monkeys. 209 30

Children with malarial infection, due to P. Vivax and P. falciparum, were tested for cell mediated immunity (CMI) by lymphocyte proliferative 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.
 ...
PMID:Cell mediated immunity in childhood malaria. 224 18

To determine the possible differences in the immune response to Plasmodium falciparum between sickle-cell trait (Hb AS) and normal haemoglobin (Hb AA) individuals, we examined 35 Hb AS and 24 Hb AA subjects matched for age and microenvironment. Their age was 2-55 years and all lived in a malaria endemic area 300 km south of Khartoum. Antibodies to ring-infected erythrocyte surface antigen (Pf155/RESA) and to circumsporozoite (CS) protein (anti-NANP40) indicated equal exposure to falciparum malaria. Peripheral blood mononuclear cells (BMNCs) from 20/35 (57%) Hb AS subjects compared with 10/24 (42%) Hb AA subjects, responded to affinity-purified P. falciparum soluble antigens (SPAg). Of those responding to SPAg, 9 (26%) Hb AS subjects and only two (8%) Hb AA subjects had high responses. The mean proliferative response to SPAg of BMNCs from Hb AS individuals was significantly higher than in Hb AA individuals (P less than 0.025). Responses of BMNCs to PPD and PHA were also higher among Hb AS individuals and correlated positively with responses to SPAg. These findings support the hypotheses that the sickle-cell trait protects individuals from P. falciparum infections, at least in part, by modulating the immune response.
 ...
PMID:Cell-mediated immune responses to Plasmodium falciparum purified soluble antigens in sickle-cell trait subjects. 228 54

The concentrations of tumor necrosis factor (TNF) produced by human peripheral blood mononuclear cells (MNC) were measured using a radioimmunoassay (RIA) for human TNF. This was developed using a rabbit antiserum against human recombinant TNF (Hu rTNF), and Hu rTNF labeled with Na125I by a modification of the chloramine T method. This RIA does not detect human lymphotoxin, interleukin-1 alpha or beta, interleukin 2, interleukin 6, interferon alpha or gamma, granulocyte-macrophage-colony stimulating factor, and C5a des arg. A good correlation (r = 0.89) was found between the RIA and the cytolytic bioassay for TNF. The sensitivity of the RIA is between 3 and 78 pg/ml (median 11 pg/ml). The mean concentration of TNF in 24-h culture supernatants of human MNC exposed to different concentrations of lipopolysaccharide (LPS) was found to increase in dose-dependent fashion and then level off between 50 and 100 ng/ml. The concentrations of IL-1 beta and alpha detected by specific RIAs in these supernatants were between 0.2 and 19 ng/ml and 0.04 and 1 ng/ml, respectively. The amount of TNF produced by human MNC in vitro was determined in a cohort of 50 normal volunteers. Without exogenous stimuli, TNF concentrations were almost always below the detection limit; with 0.5 ng/ml LPS, the median concentration of TNF was 2 ng/ml, and with PHA the median was 3.8 ng/ml. In cultures performed in the presence of indomethacin significantly (p less than 0.005) more TNF was produced. Using this RIA, we could detect TNF in the circulation of mice injected with Hu rTNF. When plasma samples of patients with febrile illnesses were added directly to the RIA, TNF was not detectable, with the exception of patients with malaria. These studies demonstrate the range and sensitivity of LPS-induced and mitogen-induced production of immunoreactive TNF by human MNC in vitro without interference of similar cytokines in bioassays.
 ...
PMID:Concentrations of immunoreactive human tumor necrosis factor alpha produced by human mononuclear cells in vitro. 325 88

Parasitologic, hematologic, and immunologic parameters were monitored in intact (nonsplenectomized), adult chimpanzees infected with a "chimp-adapted" strain of Plasmodium falciparum. Following primary and secondary injections of 10(9) P. falciparum-infected erythrocytes, each chimpanzee developed a low grade parasitemia (up to 1,000/mm3) and maintained the infection without evidence of eliminating the parasites. Hematologic and serum biochemical values, as well as the majority of immunologic parameters tested, remained unaltered in infected chimpanzees. However, 2 weeks after infection T cells from infected chimpanzees demonstrated an enhanced response in vitro to stimulation with the mitogen PHA, and monocyte phagocytic activity for antibody-coated erythrocytes (Fc-mediated phagocytosis) increased significantly. During malarial infection, apes developed a strong T cell proliferative response to P. falciparum antigens and monocytes showed enhanced phagocytic activity for P. falciparum-infected erythrocytes in the absence of immune serum. These results suggest that cellular immune mechanisms, especially macrophage activation, may help control, but not eliminate, P. falciparum malaria in chimpanzees.
 ...
PMID:Parasitologic and immunologic studies of experimental Plasmodium falciparum infection in nonsplenectomized chimpanzees (Pan troglodytes). 388 11

The distribution of T-cell subsets in acute and cerebral malaria have been studied using two monoclonal antibodies. In the course of the disease both in acute and cerebral malaria in persons living in senegalese hypoendemic area occurred important alterations of circulating T-cell subsets. A significant loss of OKT4 positive cells is observed; OKT8 positive lymphocytes are also affected but to a lesser extent. The reversal of the OKT4/OKT8 ratio found in this disease is associated with decrease responsiveness of lymphocytes to PHA. The considerable loss seen in OKT4 cells fonction could be of great importance in reducing cell mediated immune mechanisms and humoral response needed to eradicate the malaria parasite.
 ...
PMID:[T-cell subpopulations during acute attacks of pernicious malaria]. 389 48

In a study in a population in northern Tanzania, almost all adults and schoolchildren with parasitaemia were positive in the PHA test, whereas only half of the children under 5 years of age with parasitaemia were serologically positive. A second study on infants up to the age of 18 months confirmed that many young children who could be expected to have been exposed to malaria did not have PHA-detectable antibody.
 ...
PMID:Application of the passive haemagglutination test for malaria: the problem of false negatives. 454 16

The mitogen-induced DNA synthesis in vitro in lymphocytes from 20 patients acutely ill with Plasmodium falciparum malaria was compared with that of 16 healthy donors. Within both groups part of the donors were individuals who had only experienced short exposure or none at all to the parasite (Sweden) while the other part were donors living in a malaria endemic area (Colombia). The proliferative response to the T cell mitogen La (leucoagglutinin from PHA) of the patients was significantly reduced as compared with that of the controls. With pokeweed mitogen which stimulates T cells and induces a T cell-dependent activation of B cells, no difference between patients or controls was seen. The results were similar for the donors of different geographical origin and malaria background. Lymphocytes and monocytes from the peripheral blood of these donors were also studied for surface marker distribution by means of monoclonal antibodies. Both the absolute and the relative frequencies of T cells in the blood of the malaria patients were significantly reduced as compared with the controls. Furthermore, in almost all eight patients tested, the ratio between T4+ T cells (including the helper/inducer subsets) and T8+ T cells (including the suppressor and cytotoxic subsets) were below 1:1 while they were close to 2:1 in the controls. The results indicate that the relative frequency of T8+ T cells, expressed as percentage total T cells (T3+) was significantly elevated in the P. falciparum patients. The possible relationship between this imbalance and the irregular La response of the patients lymphocytes requires further investigation of lymphocyte function.
 ...
PMID:Regulation of the immune response in Plasmodium falciparum malaria. I. Non-specific proliferative responses in vitro and characterization of lymphocytes. 634 79


1 2 Next >>