Publications by authors named "Ravindran B"

Intraperitoneal implantation of adult gravid females of the bovine filarial parasite, Setaria digitata in Mastomys coucha was found to induce microfilaraemia lasting for about 125 days. The microfilariae (mf) could be detected as early as 4 days post-implantation (p.i.

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A spectrum of clinical manifestations is a feature of human lymphatic filariasis. The acute disease is characterized by periodic and self limiting episodes of adenolymphangitis, fever and associated constitutional symptoms, while the chronic disease includes long lasting manifestations such as lymphoedema and/or hydrocoele. The microfilariae carriers are generally free of clinical symptoms.

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Naturally occurring antibodies to alpha-linked galactose (anti- gal) has been reported to be present in large quantities in normal human sera and they seem to play an important role in a variety of infectious as well as autoimmune diseases. A cell-ELISA using glutaraldehyde fixed normal rabbit erythrocytes was developed for quantification of anti-gal in human sera. This assay was compared with three other(commonly used) immunoassays viz.

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Anti-phosphatidyl choline antibodies (alphaPC) have been measured in adult patients from Orissa, India with Plasmodium falciparum infection of varying clinical severity. Significantly raised levels of alphaPC were observed in infected individuals in comparison with controls. The IgG alphaPC were found to be generally more than IgM alphaPC in most cases.

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Anti-sheath antibodies have been detected using an immunofluorescent assay (IFAT) in the sera of microfilariae carriers (AS cases) residing in areas endemic for Bancroftian filariasis. Microfilariae (mf) of Wuchereria bancrofti purified from five different mf carriers were used separately as antigen to identify anti-sheath antibodies. The reactivity of sera from AS cases to mf sheath was found to be variable to the five different mf preparations.

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A differential serological screen of a lambda gt11 cDNA expression library of Plasmodium falciparum was performed in an attempt to identify novel and putative host-protective antigens of the parasite. The screening was done with two categories of sera: (i) acute-phase sera obtained from smear-positive acutely infected P. falciparum patients from various regions in India and (ii) immune sera taken from healthy, permanent adult residents of P.

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A cell-ELISA was developed using monolayers of glutaraldehyde-fixed normal as well as Plasmodium berghei-infected mouse erythrocytes for quantification and characterization of anti-erythrocytic autoantibodies in murine malaria. Testing normal (NMS) and peak parasitaemic sera (PPS) on erythrocyte monolayers treated with trypsin, sodium meta periodate, neuraminidase or heat, and competitive inhibition of antibodies with soluble sialic acid, revealed that some anti-erythrocytic antibodies (which increase during the parasitaemic phase of infection) recognize N-acetyl neuraminic acid (NANA) residues on host erythrocytes. High levels of antibodies to NANA covalently conjugated to bovine serum albumin (BSA) were detectable in PPS.

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Anti-malarial antibodies were quantified in cerebrospinal fluid (CSF) of 17 cases of cerebral malaria, 16 presumptive cases (no demonstrable parasitaemia in peripheral blood but responding to i.v. quinine therapy) of cerebral malaria, and 15 controls.

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We have used procedures which have been developed to isolate murine T cell antigen binding molecules (TABM) in order to isolate TABM from normal human sera. To begin purification, ammonium sulfate (NH4)2SO4 was added to human serum and precipitated protein was dissolved in low salt buffer and resolved by ion-exchange chromatography on carboxymethylcellulose (CM). The most strongly CM nonadherent fraction was absorbed with anti-human albumin and anti-human immunoglobulin (Ig) antibodies conjugated to Sepharose beads.

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Immunological adjuvants (alum, liposomes and saponin) were utilized to stimulate cell-mediated immune response in Plasmodium berghei infected Balb/c mice. It was shown that malaria antigen mixed with adjuvant induced appreciably delayed type hypersensitivity and production of migration inhibition factor compared to antigen alone.

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Antibodies directed towards the sheaths of microfilariae have been implicated in the elimination of circulating microfilariae, both in experimental and human filariasis. In the present study antisheath antibodies have been detected in human sera by indirect immunoperoxidase assay (IPA) using fixed Wuchereria bancrofti microfilariae as antigen. One hundred and eighteen sera collected from an area endemic for Bancroftian filariasis were tested.

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We demonstrate by an ELISA the presence of antibodies in human filarial sera that react with diethylcarbamazine (DEC); they appear to be primarily filarial antibodies cross-reacting with DEC skeleton, since affinity-purified DEC antibodies strongly react with Wuchereria bancrofti microfilariae. These observations indicate a possible antigenic mimicry between the drug and some parasite component.

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Naturally-occurring antibodies with a distinct alpha-galactosyl specificity (anti-gal) have been earlier implicated in opsonization and elimination of human senescent erythrocytes from circulation. In the present study a cell-ELISA was developed for quantification of anti-gal antibodies in human sera. Using the test, titres of anti-gal were found to be significantly elevated in many of the sera collected from subjects living in malaria endemic areas or patients with acute Plasmodium falciparum malaria, in comparison to the titres in subjects living in areas where the incidence of P.

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Antibodies directed against the microfilarial sheath have been instrumental in the immune elimination of circulating microfilariae in human lymphatic filariasis. We report here that antibodies to diethylcarbamazine (DEC, the most commonly used anti-filarial drug) cross-react with the sheath of Wuchereria bancrofti microfilariae. Antibodies with reactivity to DEC were raised in rabbits by immunization with a conjugate of methylpiperazine carboxylic acid (MPCA, an acid hydrolysis product of DEC) coupled to bovine serum albumin.

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Circulating antigens, antibodies to somatic and sheath components of microfilariae (mf) and immune complexes were determined in parallel in different categories of Wuchereia bancrofti infection using, respectively, reverse indirect haemagglutination (RIHA), indirect haemagglutination (IHA), indirect immunofluorescent (IFA) and polyethylene glycol (PEG) precipitation assays. Rabbit hyperimmune anti-W. bancrofti mf serum and mf homogenates were used as reagents.

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Kupffer cells from the liver and erythrocytes from peripheral blood were collected at the post-patent period from albino rats infected earlier with Plasmodium berghei and rhesus monkeys infected earlier with P. cynomolgi var. bastianelli or P.

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Clinically diagnosed cases with different grades of rheumatoid arthritis (RA) were studied for (a) cryoglobulin content (b) constituents of cryoglobulins, and (c) rheumatoid factor (RF) titers in sera and cryoglobulins. Of 60 patients, 28 (46.66%) had significantly high levels of cryoglobulins and were mainly distributed in the severe group.

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