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M E Patarroyo

Publications and source records attributed to M E Patarroyo.

At least 109 records · Page 6Linked to original sources
PubMed1987

Mycobacterium leprae antigen-induced suppression of T cell proliferation in vitro.

The extent to which M. leprae and its products induced suppression of T lymphocyte proliferation in vitro was evaluated. M. leprae antigens suppressed T cell proliferation in response to mitogens and antigens in both lepromatous and tuberculoid patients, as well as controls never exposed to M. leprae or M. leprae endemic areas. Both soluble and particulate fractions of M. leprae were found to suppress proliferation in a dose-dependent manner. The extent of suppression was inversely related to the proliferative response of the donors mononuclear cells to M. leprae. Evidence indicates that M. leprae contains both stimulatory and suppressive molecules for T cells. One such suppressive antigen, Lipoarabinomannan (LAM)-B of M. leprae, also suppressed the proliferative response of tuberculoid patients. Suppression was also observed with the LAM-B of M. tuberculosis. The suppressive effects observed were not due to the toxicity of the antigen. Some of the suppressive activity was mediated by T8+ suppressor cells and was expressed in both lepromatous and tuberculoid patients. We suggest that previous sensitization to M. leprae and other cross-reactive mycobacterial antigens determines the sensitivity of T cells to the suppressive effects of M. leprae antigens.

Antigens, Bacterial↗
PubMed1987

Regulation of the immune response in Plasmodium falciparum malaria: IV. T cell dependent production of immunoglobulin and anti-P. falciparum antibodies in vitro.

T cells from patients with acute Plasmodium falciparum malaria were investigated for induction of immunoglobulin- or anti-malaria antibody secretion in vitro. Stimulation of autologous T/B cell mixtures (2T:1B) with low concentrations of P. falciparum antigen and cultured for 12 days gave rise to a T-dependent IgG secretion which was significantly elevated over that in medium controls. This was achieved with both a crude P. falciparum antigen and a partially purified preparation enriched in Pf 155, a merozoite-derived antigen deposited in the red cell membrane at invasion (Perlmann et al., 1984). Control antigen (RBC ghosts) induced IgG secretion only when added at high concentrations (greater than 10 micrograms/ml). Neither of the antigens induced IgG secretion at concentrations of less than or equal to 10 micrograms/ml in control cultures of lymphocytes from patients with P. vivax malaria. Supernatants from cultures of P. falciparum patients frequently contained anti-P. falciparum antibodies when nanogram quantities (10-100 ng/ml) of either one of the two malaria antigen preparations was used for stimulation. No anti-P. falciparum antibodies were induced by the control antigen at any concentration. The induced anti-P. falciparum antibodies were directed to intracellular parasites and. at lower frequencies, to Pf 155 as detected on the surface of infected erythrocytes. The induction in vitro of anti-P. falciparum antibodies appeared to be correlated with the presence of such antibodies in the sera of the lymphocyte donors. The lymphocytes of only one out of eight P. vivax patients responded to antigen stimulation by secreting anti-P. falciparum antibodies. However, this donor (but not any of the others), was also P. falciparum seropositive. Taken together, these results indicate that the induction of anti-P. falciparum antibody secretion reflects a secondary response in vitro of cells primed in vivo. The present experimental system should be well suited to map parasite antigen for their capacity to induce T cell dependent responses in P. falciparum malaria.

Acute Disease↗
PubMed1986

Rabbit and human antibodies to a repeated amino acid sequence of a Plasmodium falciparum antigen, Pf 155, react with the native protein and inhibit merozoite invasion.

The Plasmodium falciparum-derived antigen of Mr 155,000 designated Pf 155, deposited in the membrane of infected erythrocytes, contains at least two blocks of tandemly repeated amino acid sequences. The peptide Glu-Glu-Asn-Val-Glu-His-Asp-Ala, which corresponds to a subunit of a C-terminally located repeat, was synthesized. Rabbits immunized with the octapeptide conjugated with either keyhole limpet hemocyanine or tetanus toxoid formed antibodies against the octapeptide. These antibodies reacted with Pf 155 as detected by immunoblotting or a modified immunofluorescence assay. Sera from humans exposed to P. falciparum also contained antibodies binding to the octapeptide in a dot-blot immunoassay. Their anti-octapeptide titers were correlated with their immunofluorescence titers in the assay detecting Pf 155 and other parasite antigens in the membrane of infected erythrocytes. Human octapeptide-reactive antibodies were isolated on an affinity column with the octapeptide conjugated to bovine serum albumin as ligand. These human antibodies reacted with Pf 155 in immunoblotting and strongly stained the surface of infected erythrocytes in the modified immunofluorescence assay. Approximately 20% of this immunofluorescence activity in a high-titered human serum could be recovered from the octapeptide column, indicating that a significant fraction of these anti-parasite antibodies react with epitopes associated with the octapeptide. Furthermore, the human octapeptide-reactive antibodies very efficiently inhibited merozoite reinvasion into erythrocytes in vitro. Similarly purified rabbit antibodies also significantly inhibited reinvasion. Our results suggest that the C-terminal segment of repeated peptides in Pf 155 is a major antigenic region of the molecule and may contain target sites for protective immunity in P. falciparum malaria.

Amino Acid Sequence↗
PubMed1986

Properties of proteins MPB64, MPB70, and MPB80 of Mycobacterium bovis BCG.

The immunogenic proteins MPB64 and MPB80 of Mycobacterium bovis BCG were purified to homogeneity and compared with MPB70. MPB70 and MPB80 showed a similar distribution in substrains of BCG, both being present in high concentrations in culture fluids of BCG substrain Tokyo, BCG Moreau, BCG Russia, and BCG Sweden and in only very small amounts in BCG Glaxo, BCG Tice, BCG Copenhagen, and BCG Pasteur. In various physicochemical properties MPB70 and MPB80 were closely similar, but MPB80 had a distinctly lower pI value. The N-terminal amino acid sequence was identical for the first 30 residues. In reactions with anti-MPB70 antibodies and delayed-type hypersensitivity skin reactions, MPB70 and MPB80 also had very similar properties. These results show that MPB70 and MPB80 are two closely similar forms of the same gene product, and postsynthetic changes probably explain the observed differences. By contrast, MPB64 had a higher molecular weight. The N-terminal amino acid sequence showed no homology with MPB70, and these two proteins showed no immunologic similarity. MPB64 and MPB70 showed only very restricted cross-reactivity with other species of mycobacteria but cross-reacted with Nocardia asteroides. The similar occurrence in eight different substrains of BCG indicated that the two proteins are influenced by similar control mechanisms, but in contrast to MPB70, MPB64 occurred in sufficient concentration in two strains of Mycobacterium tuberculosis to give a distinct spot in two-dimensional polyacrylamide gel electrophoresis of their culture fluids.

Amino Acid Sequence↗
PubMed1986

MPB59, a widely cross-reacting protein of Mycobacterium bovis BCG.

The MPB59 protein of Mycobacterium bovis BCG was purified to homogeneity from culture fluid of BCG substrain Tokyo, and characterized by biochemical and immunological techniques. The molecular weight was 28,000, determined by SDS-polyacrylamide gel electrophoresis, and the pI value was 5.3. The N-terminal amino acid sequence was determined for 32 steps and showed no significant homology with MPB64, MPB70 or MPB80. By crossed immunoelectrophoresis, MPB59 was found to belong to the BCG antigen 85 complex and identified as corresponding to the 85B component of this complex. The protein cross-reacted extensively with other species of mycobacteria, and induced a marked humoral immune response in armadillos and monkeys during development of systemic mycobacterial infection after inoculation with Mycobacterium leprae.

Amino Acid Sequence↗
PubMed1985

An analysis of in vitro T cell responsiveness in lepromatous leprosy.

In lepromatous leprosy, there is extensive replication of Mycobacterium leprae (M. leprae) within dermal macrophages. This lack of microbial resistance has been attributed to a defective cell-mediated immune response to M. leprae antigens. We have examined the in vitro response of T cells to M. leprae to determine if hyporesponsiveness could be reversed. The study included 40 unselected patients from New York and from Colombia, most with the severe lepromatous form of the disease. We first noted that lepromatous leprosy patients were of two types: those unable to respond, as assessed by T cell proliferation and immune (gamma) interferon (IFN-gamma) release, and a second group, exhibiting low but detectable responses relative to tuberculoid controls. When the effect of exogenous recombinant interleukin-2 (IL-2) on the response to M. leprae antigens was compared in the two groups, many of the low responders, but not the nonresponders, showed enhanced proliferation and IFN-gamma release. To evaluate a possible suppressive effect of monocytes, these cells were eliminated with a cell-specific monoclonal antibody and complement. Depletion of monocytes often expanded preexisting weak responses but did not reverse the anergy of the M. leprae nonresponders. The enhancement was not M. leprae-specific, since it was also observed when bacillus Calmette-Guerin was the antigenic stimulus for proliferation and IFN-gamma production. Removal of the suppressor T cell subset, with OKT8 antibody and complement, also did not restore responses in nonresponder patients. We conclude that a sizable number of lepromatous leprosy patients exhibit a low degree of responsiveness to M. leprae and that the responses can be enhanced in vitro with IL-2 or with monocyte depletion. Nonresponsiveness, however, cannot be reversed. Since currently available assays measure the function of previously sensitized T cells, suppressor mechanisms may yet contribute to defective cell-mediated immunity by impairing the initial sensitization to M. leprae antigens.

Adult↗
PubMed1985

Production of IL 2 and IFN-gamma by T cells from malaria patients in response to Plasmodium falciparum or erythrocyte antigens in vitro.

T cells from patients acutely infected with malaria exhibit a disease-related stimulation of DNA synthesis in response to Plasmodium falciparum antigen in vitro. This response is weak and short-lived, suggestive of induction of suppressor mechanisms. Exogenous T cell growth factor (IL 2) that was added to antigen-stimulated T cell cultures enhanced proliferation in antigen-responsive cultures, indicating that the lymphocytes expressed IL 2 receptors. In contrast, the addition of IL 2 to cultures that did not respond to antigen had no effect. Antigen-responsive cultures contained endogenous IL 2 as well, and the antigen-induced lymphocyte proliferation was correlated with IL 2 production. However, the results suggested that IL 2 production by the patients' T cells was insufficient or actively shut off, and that this was responsible for the premature cessation of their DNA synthesis. Supernatants from 60% of the T cell cultures treated with malaria antigen and from 30% treated with RBC ghost antigen contained interferon-gamma (IFN-gamma), as determined by a cytopathic effect inhibition assay combined with acid treatment and antibody neutralization or by an IFN-gamma-specific ELISA. There was no obvious correlation between antigen-induced lymphocyte proliferation and the presence of IFN-gamma in the culture supernatants. A high IFN-gamma activity was also seen in antigen-treated cultures from P. falciparum-immune donors living in highly endemic malaria areas. In contrast, no IFN-gamma was found in supernatants of antigen-treated T cells from healthy donors or patients with Plasmodium vivax malaria. Thus, the IFN-gamma activity of these cultures appears to reflect the presence of antigen-reactive T cells and may be useful as a sensitive indicator of cellular immunity in P. falciparum malaria.

ABO Blood-Group System↗
PubMed1984

Antibodies in malarial sera to parasite antigens in the membrane of erythrocytes infected with early asexual stages of Plasmodium falciparum.

Monolayers of human erythrocytes (E) infected with Plasmodium falciparum were briefly fixed with 1% glutaraldehyde and air dried. They were then exposed to sera from patients with P. falciparum malaria or from donors immune to this parasite and tested in an indirect immunofluorescence assay (IFA). Parasites in infected E were made visible by counterstaining with ethidium bromide. Immunofluorescence (IF) was restricted to the surface of infected E. No antibody binding was detected unless the E were dried, suggesting that the relevant antigens were not available on the outer layers of the E surface. Staining over large parts of the E surface was seen already when the merozoite penetrated noninfected cells and was strong in E containing early stages of the parasite (rings, trophozoites). It was weak or absent from E containing schizonts. Antibodies in sera from different parts of Africa, Colombia, or Sweden reacted similarly with E infected with a Tanzanian P. falciparum strain kept in culture for many years and with parasitized E freshly drawn from African, Swedish, or Colombian patients. All sera from residents of a holoendemic area (Liberia) were IFA positive. In contrast, some sera from Colombian or Swedish patients with primary infection gave negative results. The results of the IFA and of an enzyme-linked immunosorbent assay in which fixed and dried E were the targets were well-correlated, suggesting that the same antibodies were detected by these assays. The antigens involved in the IFA were susceptible to pronase but not to trypsin or neuraminidase. E surface IF was inhibited by lysates of infected E, merozoite extracts, or soluble antigens present in P. falciparum culture supernatants but not by lysates of normal E or ghost extracts. The inhibitory antigens were heat stable (100 degrees C, 5 min). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblotting of either antigen-enriched preparations from culture supernatants or merozoite extracts showed that antibodies eluted from monolayers of infected E reacted consistently with a predominant polypeptide of Mr 155,000 and two to four minor polypeptides of lower molecular weights. Metabolic labeling of the parasites with 75Se-methionine indicated that these antigens were parasite derived. We conclude that the antigens involved in these reactions are released from bursting schizonts or merozoites and are deposited in the E membrane in the course of invasion.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies↗
PubMed1984

Human antibodies to a Mr 155,000 Plasmodium falciparum antigen efficiently inhibit merozoite invasion.

IgG from a donor clinically immune to Plasmodium falciparum malaria strongly inhibited reinvasion in vitro of human erythrocytes by the parasite. When added to monolayers of glutaraldehyde-fixed and air-dried erythrocytes infected with the parasite, this IgG also displayed a characteristic immunofluorescence restricted to the surface of infected erythrocytes. Elution of the IgG adsorbed to such monolayers gave an antibody fraction that was 40 times more efficient in the reinvasion inhibition assay (50% inhibition titer, less than 1 microgram/ml) than the original IgG preparation. The major antibody in this eluate was directed against a parasite-derived antigen of Mr 155,000 (Pf 155) deposited by the parasite in the erythrocyte membrane in the course of invasion. A detailed study of IgG fractions from 11 donors with acute P. falciparum malaria or clinical immunity revealed the existence of an excellent correlation between their capacities to stain the surface of infected erythrocytes, their titers in reinvasion inhibition, and the presence of antibodies to Pf 155 as detected by immunoblotting. No such correlations were seen when the IgG fractions were analyzed for immunofluorescence of intracellular parasites or for the presence of antibodies to other parasite antigens as detected by immunoprecipitation of [35S]methionine-labeled and NaDodSO4/PAGE-separated parasite extracts. The results suggest that Pf 155 has an important role in the process of erythrocyte infection and that host antibodies to this antigen may efficiently interfere with this process.

Adolescent↗
PubMed1984

Regulation of the immune response in Plasmodium falciparum malaria. III. Proliferative response to antigen in vitro and subset composition of T cells from patients with acute infection or from immune donors.

T cells from patients with acute Plasmodium falciparum malaria were investigated for their proliferative responses in vitro to malarial antigen. Of 26 patients, 14 had acute and short lived (less than or equal to 8 days) disease episodes, most of them for the first time, while 12 had been ill for more than 8 days at the time of the blood samples were taken. The lymphocytes from the first group gave a weak, and apparently P. falciparum specific proliferation, peaking after 3-4 days, but waning within 5-6 days, suggesting the induction of suppression. No such responses were obtained with control antigen consisting of normal RBC membranes. The P. falciparum antigen-induced proliferative response was completely lacking in the second group of patients. Since both groups responded equally to T cell mitogen, the results are indicative of a malaria specific non-responsiveness. In contrast T cells from a group of apparently immune donors living in highly endemic P. falciparum malaria areas developed strong and long lasting proliferative responses to P. falciparum antigen with a peak on days 5-6. T cells from acutely infected P. vivax patients did not respond to either the P. falciparum antigen or to the control antigen. The cellular basis of the proliferative responses were investigated by surface marker studies with monoclonal antibodies. Within the T cell preparations, the T4+/T8+ cell ratio was close to normal for both the immune donors and for those with acute P. vivax infection. In contrast, this ratio was depressed for both groups of patients with acute P. falciparum infection. However, this was due to reduced number of circulating T4+ cells in the patients with short disease episodes whereas it was due to increased numbers of T8+ cells, probably including suppressor cells, in those who were ill for more than 8 days.

Antibodies, Monoclonal↗
PubMed1983

Regulation of the immune response in Plasmodium falciparum malaria. II. Antigen specific proliferative responses in vitro.

The antigen-induced DNA synthesis in vitro in lymphocytes from patients with acute Plasmodium falciparum malaria was investigated. The patients and healthy controls from Sweden or Colombia were the same as those studied in the accompanying paper (Troye-Blomberg et al., 1983). The malarial antigens used were sonicated membrane preparations or purified and concentrated supernatants from in vitro cultures of P. falciparum; similar preparations derived from normal human erythrocytes served as control antigen. In the patients' lymphocytes P. falciparum antigens induced a weak or moderate but significant stimulation of DNA synthesis, peaking after 3-4 days of incubation. This early response was specific for P. falciparum since it was not obtained with lymphocytes from healthy donors nor with those from patients with acute P. vivax or P. ovale malaria. No antigen-induced response was seen in about half of the P. falciparum patients. However in a few negative cases, available for consecutive testing, positive reactions were seen with lymphocytes taken 2 weeks after infection when the blood of these patients was free of parasites. The early response induced in patients' lymphocytes to the P. falciparum antigens was not obtained with RBC antigen. However, these preparations frequently induced a response rising to significant levels later during incubation (day 5-6). Similar delayed responses were obtained when either patients' or control donors' lymphocytes were exposed to the P. falciparum antigens. This indicates that both the RBC and the parasite preparations contained mitogenic substances affecting human lymphocytes in general and easily obscuring the P. falciparum specific response seen only in the patients. This latter response was relatively low and short lived, suggesting that it reflected a secondary in vitro stimulation of in vivo primed lymphocytes and that it was regulated by suppressor mechanisms.

Acute Disease↗
PubMed1983

Regulation of the immune response in Plasmodium falciparum malaria. I. Non-specific proliferative responses in vitro and characterization of lymphocytes.

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.

Acute Disease↗
PubMed1979

Chronic Lyme arthritis. Clinical and immunogenetic differentiation from rheumatoid arthritis.

Ten patients with Lyme arthritis have developed chronic involvement of one or both knees. Lyme arthritis was diagnosed by onset with erythema chronicum migrans (six patients); residence in Lyme, Connecticut (eight); seasonal onset in summer and early fall (nine); early periods of short recurrent attacks (nine); absence of rheumatoid factor (nine); and absence of symmetrical polyarthritis, morning stiffness, subcutaneous nodules, or antinuclear antibodies (in all). Five patients had synovectomies; pannus formation and underlying cartilage erosion were present in all. Seven of the 10 patients had the same B-cell alloantigen, DRw2 (frequency in normal control subjects, 22% [P less than 0.005]), but did not have an increased frequency of the alloantigens associated with rheumatoid arthritis. Chronic Lyme arthritis, the result of an apparent tick-transmitted infection, resembles rheumatoid arthritis pathologically but generally differs from it in both prearticular and immunogenetic characteristics.

Adolescent↗
PubMedDate not supplied

Viral hepatitis in Colombia: a study of the "hepatitis of the Sierra Nevada de Santa Marta".

The prevalences of hepatitis B virus (HBV), hepatitis delta virus and hepatitis A virus infections were studied in two regions of Colombia. In Bogota, 10 of 53 patients with acute hepatitis were HBsAg positive and three of these were hepatitis D antigen positive. Hepatitis A virus was the major cause of acute hepatitis in this group. In 366 healthy controls from Bogota, 1.6% were HBsAg positive and 7.1% had at least one marker of HBV infection. In northern Colombia, individuals from three villages with outbreaks of the fulminant "hepatitis of the Sierra Nevada de Santa Marta" were tested. The prevalences of HBsAg (1.8 to 23%) and HBV infection (35 to 93%) were generally high and varied from village to village; 60% of the HBsAg carriers in one village were positive for antibody to hepatitis D antigen, and two individuals in the outbreak area had circulating hepatitis D antigen. The findings suggest that HBV and the associated hepatitis delta virus are etiologic factors in the "hepatitis of the Sierra Nevada de Santa Marta."

Adolescent↗