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Biomedical subjects

V R Muthukkaruppan

Publications and source records attributed to V R Muthukkaruppan.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of a commercial rubella IgM assay for use on oral fluid samples for diagnosis and surveillance of congenital rubella syndrome and postnatal rubella.

BACKGROUND: Clinical diagnosis (surveillance) of rubella is unreliable and laboratory confirmation is essential. Detection of virus specific IgM in serum is the most commonly used method. However, the use of serum necessitates the drawing of blood, either through venipuncture or finger/heel prick, which can be difficult in young babies. Oral fluid samples have proved useful as an alternative, less invasive sample for virus specific IgM detection however until recently no commercial rubella IgM tests were available, restricting the usefulness of this approach. OBJECTIVES: To evaluate the performance of the Microimmune Rubella IgM capture EIA using oral fluid samples from outbreaks as well as in cases of suspected congenital rubella syndrome (CRS). STUDY DESIGN: Paired serum and oral fluids were collected from cases during a rubella outbreak in three provinces in Turkey. Matched serum and oral fluid samples were collected from children with suspected CRS in an active surveillance programme at the Aravind Eye Hospital in South India. Serum samples were collected as part of the measles surveillance programme in Ethiopia. RESULTS: On serum samples the sensitivity and specificity of the Microimmune Rubella IgM capture EIA compared to Behring Enzygnost rubella IgM test was 96.9% (62/64; 95% CI 94.2-100%) and 100% (53/53; 95% CI 93.2-100%). On oral fluids compared to matched Behring results on serum the sensitivity was 95.5% (42/44; 95% CI 84.5-99.4%). The sensitivity and specificity of Microimmune Rubella IgM capture EIA on oral fluids from suspected CRS cases compared to serum results using Behring Enzygnost IgM assay was 100% (95% CI 84.5-100%) and 100% (95% CI 95.8-100.0%) respectively. CONCLUSION: Microimmune Rubella IgM capture EIA has adequate performance for diagnosis and surveillance of rubella in outbreak using either serum or oral fluid specimens.

Antibodies, Viral↗
PubMed2003

Identification and evaluation of LPS antigen for serodiagnosis of uveitis associated with leptospirosis.

Leptospirosis is a widespread zoonotic disease that affects all mammals in different parts of the world. Though there are many commercial kits available for the diagnosis of systemic leptospirosis, the nature of the antigen has not been described. Therefore, identification of a specific antigen is important. Since ocular involvement in leptospirosis has been reported, there is a need to identify and characterize the leptospiral antigen for diagnosis of uveitis associated with past leptospiral infection (leptospiral uveitis) and for confirming the clinical diagnosis. Seven-day-old culture of Leptospira biflexa serovar Patoc was used for preparing the antigen. The present study included serum samples from 81 patients with clinical criteria for leptospiral uveitis, 15 cataract controls and 15 non-leptospiral uveitis controls. Serum samples were assayed by ELISA using our antigenic preparation and by a microscopic agglutination test (MAT) using 19 serovars. The antigen prepared had 280 micro g LPS ml(-1) and no detectable amount of protein. Silver-staining of SDS-PAGE for protein and LPS, dot blot and Western blot analysis and proteinase K and periodate treatment showed that LPS (13-21 kDa and 28 kDa) in our preparation was the relevant antigen for serodiagnosis. IgG antibodies showed reactivity in both leptospiral uveitis patients and controls. However, on the basis of IgM response to LPS, 48 % of the leptospiral uveitis patients were significantly positive compared with controls; 58 % of leptospiral uveitis patients and none of the controls were positive for MAT. When MAT and IgM ELISA results were considered together, 77 % were significantly positive. LPS is identified as a candidate antigen for serodiagnosis of leptospiral uveitis and has sensitivity and specificity of 48 and 90 %, respectively, in ELISA for IgM antibodies. Confirmation of clinical diagnosis with a specific laboratory test would help to initiate the most appropriate treatment for leptospiral uveitis.

Adult↗
PubMed1999

Influence of immunopotentiators on the antiporin immunoglobulin G subclass: distribution and protective immunity against murine salmonellosis.

To improve the immune potential of porin (a pore-forming protein of Salmonella sp.), different immunopotentiators such as Freund's complete adjuvant (FCA), lipopolysaccharide (LPS) and polyoxydonium (PO) were evaluated by studying the nature of the protective immune response induced against murine Salmonellosis. The nontoxic, synthetic heteropolymer polyoxydonium was as good as LPS at inducing antiporin immunoglobulin G (IgG) antibodies and protective immunity. Analysis of the antiporin IgG subclass pattern revealed a preferential increase in a particular subclass based on the immunopotentiator used. Porin, alone or emulsified in FCA, elicited predominantly antiporin IgG1 antibodies, whereas LPS preferentially evoked antiporin IgG2a, IgG2b and IgG3 antibodies. Polyoxydonium induced a clear shift towards antiporin IgG2b antibodies. The significance of these antiporin IgG subclass antibodies in protection against murine Salmonellosis was studied by passive immunization and by analysing the infected mouse sera.

Adjuvants, Immunologic↗
PubMed1995

IgG subclass antibodies to mycobacterial sonicate and recombinant antigens in leprosy.

In this study the IgG subclass antibodies to sonicated preparations of Mycobacterium leprae (leprosin A) and BCG (BCG-S) as well as to purified recombinant 65 kDa protein of M. leprae (rML65) were analysed in sera from leprosy patients and healthy household contacts (HFC) and noncontacts (HNC) in a leprosy endemic population. In LBI+ (lepromatous bacterial index positive) patients, IgG3 was predominant in the responses to sonicated antigens of M. leprae. Following chemotherapy, IgG3 responses were reduced while IgG2 levels were increased. On the other hand, IgG response to rML65 was dominated by IgG1 in all the patient and control groups. Interestingly, the level of antileprosin A IgG antibody in erythema nodosum leprosum (ENL) was similar to that of lepromatous groups, while the level of anti-rML65 IgG antibody was significantly reduced in ENL. IgG4 antibodies to the antigens studied were only at low levels in all groups, including ENL. Significant differences were observed between HNC and HFC in the pattern of IgG subclass antibodies to sonicated antigens, even though their antigen specific IgG levels were similar. While HNC showed equivalent proportion of IgG1 and IgG2 in their responses to leprosin A and BCG-S, HFC showed a specific increase in IgG1 levels, suggesting that both groups are distinctly different. Further studies are required to elucidate the functional significance of IgG subclass pattern in pathogenesis and the mechanism of immunoregulation resulting in the high levels of IgG1 and IgG3 antibodies to M. leprae protein antigens in lepromatous leprosy.

Adolescent↗
PubMed1994

Cellular and humoral immune responses to recombinant 65-kD antigen of Mycobacterium leprae in leprosy patients and healthy controls.

Cellular and humoral immune responses to recombinant 65-kD antigen of Mycobacterium leprae (rML65) were studied in leprosy patients and healthy contacts from a leprosy-endemic population. Peripheral blood mononuclear cells from a considerable proportion of tuberculoid leprosy patients, healthy contacts and non-contacts showed proliferative response to rML65 in vitro. A strong positive correlation was observed between the responses to rML65 and bacille Calmette-Guérin (BCG) or leprosin A. Addition of recombinant IL-2 (rIL-2) enhanced the proportion of responders to rML65 considerably in all groups of leprosy patients, healthy contacts and non-contacts. Among lepromatous patients this enhancement was more pronounced in the bacterial index (BI)-negative group. These results indicate that the 65-kD antigen of Myco. leprae is a dominant T cell immunogen in our study population. Though lepromatous patients showed poor lymphoproliferative response to rML65, their IgG antibody levels to the same antigen were markedly high. Most of the BI-positive lepromatous patients with elevated anti-rML65 IgG levels did not show T cell reactivity even with the addition of rIL-2. On the other hand, tuberculoid leprosy patients, healthy contacts and non-contacts showed good T cell reactivity but low levels of IgG antibodies to rML65, thus indicating the presence of an inverse relationship between cell-mediated and humoral immune responses to a defined protein antigen of Myco. leprae in humans. A significant proportion of individuals among tuberculoid leprosy patients, healthy contacts and non-contacts showed neither T cell reactivity nor elevated levels of IgG antibody to rML65. However, in most of these subjects, a T cell response to rML65 was demonstrable with the addition of rIL-2. These results are discussed with reference to the immunoregulatory mechanisms occurring during Myco. leprae infection on the basis of differential activation of Th1 and Th2 subsets.

Antibodies, Bacterial↗
PubMed1994

T lymphocyte reactivity of leprosy patients and healthy contacts from a leprosy-endemic population to delipidified cell components of Mycobacterium leprae.

In this study, we measured in vitro proliferative responses of peripheral blood mononuclear cells from both leprosy patients across the clinical spectrum and also healthy contacts from a leprosy-endemic population to delipidified cell components of Mycobacterium leprae (DCC) and Dharmendra lepromin. Dharmendra lepromin was poor in inducing in vitro T cell proliferation in all the study groups, even though it elicited marked in vivo skin test reaction in tuberculoid leprosy patients and healthy contacts. In contrast, Dharmendra preparation of BCG induced marked T-cell response in tuberculoid as well as bacterial index negative lepromatous patients. DCC induced a significantly higher lymphoproliferative response than Dharmendra lepromin in all study groups. A significant positive correlation was observed between the lymphoproliferative responses to DCC and BCG. The present study, based on a large number of leprosy patients and healthy contacts, clearly demonstrates that DCC, depleted of glycolipids and lipopolysaccharides, is a good antigenic preparation for evaluating T-cell reactivity to M. leprae.

Adolescent↗
PubMed1993

Mechanism of protective immunity induced by porin-lipopolysaccharide against murine salmonellosis.

Investigations were undertaken to characterize the protective immunity induced by porin-lipopolysaccharide (LPS) against Salmonella typhimurium infection in mice. Mice immunized with porin-LPS showed higher levels of antiporin immunoglobulin G than mice which received porin alone. Further, T cells from porin-LPS-immunized mice showed an augmented proliferative response to porin in vitro compared with the response of T cells from porin-injected animals. The passive transfer of anti-LPS antibodies conferred significant protection (17%), while antiporin serum failed to protect mice against lethal challenge, indicating the protective ability of anti-LPS antibodies. However, the transfer of serum obtained from porin-LPS-immunized mice resulted in better protection (30%) than did anti-LPS or antiporin antibodies alone. In contrast to LPS, monophosphoryl lipid A completely failed to induce protection against lethal infection. However, comparable to the effect of LPS, injection of porin with monophosphoryl lipid A enhanced antibody response and the protective ability of porin (81.25%). The transfer of T cells from porin-LPS-immunized mice provided higher levels of protection (47%) against lethal challenge than did T cells from porin-immunized mice (23%). The combination of T cells and serum from porin-immunized mice transferred 36% protection. However, a combination of T cells and serum from porin-LPS-immunized mice conferred the highest level of protection (92%), which was reflected by the number of survivors (100%) in the porin-LPS-immunized group. These results demonstrate that besides the protective effect of anti-LPS antibodies, the ability of LPS to augment humoral and cell-mediated immune responses to porin confers effective protection against Salmonella infection.

Animals↗
PubMed1993

A ribonuclease inhibitor expresses anti-angiogenic properties and leads to reduced tumor growth in mice.

Our experiments were designed to determine whether recombinant ribonuclease inhibitor (RNasin) could inhibit angiogenesis and reduce tumor growth in adult mice. We used the Fajardo disc angiogenesis assay as the primary means of measuring new blood vessel growth. This assay measures the penetration of cells into a polyvinyl alcohol sponge with a central core of ELVAX-coated sponge containing test substances. Cell penetration was reduced to 29.3% of control (phosphate-buffered saline; heat-inactivated RNasin) values. Endothelial cell influx was measured by lectin staining and confirmed by culturing cells isolated from sponges by collagenase treatment. RNasin also reduced the augmented reaction evoked by either basic fibroblast growth factor (bFGF) or sodium orthovanadate. To confirm the anti-angiogenic activity of RNasin, Hydron-coated polyvinyl sponges containing bFGF or bFGF plus RNasin were implanted into adult mouse corneas. bFGF induced a strong angiogenic response that was almost completely inhibited by RNasin. RNasin-containing ELVAX-coated sponges implanted subcutaneously underneath an intradermal inoculum of C755 mammary tumor cells caused significant reduction in tumor growth (P < 0.005). The antitumor effect of RNasin correlated with its effect on tumor-induced neovascularization, suggesting that the ability of RNasin to affect tumor growth was due to its ability to inhibit angiogenesis.

Adenocarcinoma↗
PubMed1992

Monoclonal antibodies against Salmonella porins: generation and characterization.

Monoclonal antibodies (mAbs) were generated against porins, one of the major outer membrane proteins of Salmonella typhi. Six clones, designated MP1, MP2, MP3 (IgG2ak), MPN4, MPN6 (IgG1k) and MPN5 (IgG2bk) were characterized by enzyme immunoassay (ELISA) for their reactivity to porins from S. typhi, Salmonella paratyphi A, S. paratyphi B, S. paratyphi C, Salmonella choleraesuis, Salmonella enteritidis, Salmonella krefeld, Salmonella panama, Salmonella typhimurium, Escherichia coli B, Shigella flexneri 1b and Pseudomonas aeruginosa. All the clones positive for S. typhi porins showed varying reactivity towards several Salmonella species. However, none of them was positive for porins from other Gram-negative bacteria or for lipopolysaccharide (LPS). The affinity constant of these mAbs, except MPN4, was found to be in the higher range. Dot ELISA revealed that the mAbs recognized porins only in their native form. The results of inhibition ELISA using horseradish peroxidase (HRP)-conjugated MP1 suggest that the clones MP1, MP2, MP3, MPN5 and MPN6 secreted antibodies to identical epitope(s) of a 36-kDa peptide and MPN4 to a different epitope of a 35-kDa peptide. The possible applications of these mAbs were discussed.

Animals↗
PubMed1992

Detection of porin antigen in serum for early diagnosis of mouse infections with Salmonella typhimurium.

The monoclonal antibodies to porin, an outer membrane protein isolated from Salmonella typhimurium and sandwich enzyme linked immunosorbent assay (ELISA) has made possible the detection of porin from sera of S. typhimurium-infected mice. The specificity of the monoclonal antibodies was ascertained based on their cross-reactivity with porins isolated from S. typhi, Shigella flexneri and Escherichia coli and lipopolysaccharide (LPS) of S. typhimurium and E. coli. Serum samples were found to be positive for porin as early as 3 days after intravenous and 5 days after oral infection. In addition, a positive correlation was observed between the bacterial load and the concentration of porin detected in the sera. On the other hand, analysis of sera for anti-porin antibody showed diametrically opposite time kinetics with antigenaemia. These results indicate that porin accumulates in the serum of infected mice much earlier than the appearance of antibodies to porin. Thus detection of porin holds promise for early diagnosis of typhoid.

Animals↗
PubMed1991

Flow cytometric analysis of CD2 modulation on human peripheral blood T lymphocytes by Dharmendra preparation of Mycobacterium leprae.

It has been reported previously that Mycobacterium leprae modulated CD2 on human peripheral blood T lymphocytes and that this modulation was accompanied by a marked reduction in the proliferative response of these cells to mitogens and antigens. In this study, we report that treatment of peripheral blood mononuclear cells from healthy individuals with Dharmendra preparation of M. leprae inhibited their ability to form rosettes with sheep red blood cells. Flow cytometric analysis of Dharmendra lepromin-treated cells showed that, in addition to CD2, CD4 and CD8 were modulated while the surface expression of CD3 was not affected. The specificity of CD2 modulation was confirmed by similar effects of Dharmendra lepromin on thymocytes and lymph node cells from human CD2 transgenic mice. The modulatory effect of Dharmendra lepromin was not observed at lower temperatures. Dharmendra lepromin treatment of activated T cells resulted in reduced binding of monoclonal antibodies to IL-2R and D66 epitope of CD2. The modulatory effects were not observed with Dharmendra preparation of BCG or other preparations of M. leprae. Our results indicate that certain M. leprae factor(s) specifically modulate(s) CD2, CD4, CD8 and IL-2R but not CD3 on T lymphocytes. The suppressive effect of Dharmendra lepromin on the T-cell proliferative response reported earlier may be explained by its modulatory effect on a number of T-cell surface molecules.

Animals↗
PubMed1990

Immunoregulatory processes induced by carrageenan in BALB/C mice.

This paper describes the induction of immunosuppression by multiple injections of Carrageenan-lambda (cgn) in BALB/C mice. While cgn alone induced non-specific suppression that persisted up to 25 days, priming with sheep red blood cells (SRBC) of mice within 10 days after cgn treatment prolonged the suppressive state. When these mice were given a secondary challenge 45 days after priming antigen (SRBC) specific suppression was observed. Thus multiple cgn treatment and priming with SRBC generated non-specific and specific suppressive states which were transferable by Thy 1+ Lyt 2+ splenocytes. Further using Indomethacin (Indo), an inhibitor of prostaglandin E2 (PGE2) synthesis, a significant reduction in the duration of suppressive state was achieved. Besides PGE2 induction, cgn treatment also prevented the augmentation of Ia+ macrophages in peritoneal exudate cells upon priming and the synthesis of thymocyte co-stimulating factor. The possible "microenvironment" created by cgn-SRBC administration that may help the induction of transferable suppression is discussed.

Animals↗
PubMed1990

Analysis of carrageenan-induced suppression of antibody response.

This paper describes the induction of immunosuppression by multiple injections of carrageenan-lambda (cgn) in BALB/c mice. While cgn alone induced non-specific suppression that persisted for up to 25 days, priming with sheep red blood cells (SRBC) of mice within 10 days of cgn treatment prolonged the suppressive state. Also, antigen (SRBC)-specific suppression was observed when these mice were given a secondary challenge 25-30 days afer priming. Thus multiple cgn treatment along with priming SRBC generated non-specific and specific suppressive states which were transferable by Thy-1+ Lyt-2+ splenocytes.

Animals↗
PubMed1989

Influence of carrageenan on peritoneal macrophages.

BALB/c mice were given five intraperitoneal (i.p.) injections of lambda carrageenan (CGN lambda). Following this treatment, the viability, phagocytic capacity, bactericidal activity, interleukin 1 (IL-1)-producing ability and Ia+ cell content of the peritoneal plastic-adherent macrophage population was analysed. The present study demonstrates the enhancement of bactericidal activity, inhibition of the augmented Ia+ cell content after priming with sheep red blood cells (SRBC), and impairment of IL-1 production by peritoneal macrophages, although their viability and phagocytic function remained unaltered.

Animals↗
PubMed1989

Biochemical analysis of serum proteins from Eales' patients.

In the present study attempt has been made to identify the possible factor(s) which are responsible for Eales' disease. The serum of Eales' patients and that of age and sex matched healthy controls did not differ in their total protein concentration. Sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE) analysis did not reveal any difference between the two groups. However, analysis of the serum samples with isoelectric focusing showed the presence of two unique proteins with pI of 5.5 and 5.9 in Eales' patients. Further two dimensional SDS-PAGE analysis indicated the presence of a distinct protein spot with a pI of 5.9 and a molecular weight around 23 KD in the serum of Eales' patients. This 23 KD protein has been partially purified and found to be anionic in nature. Antisera to this partially purified protein have been raised and tested. The implication of this finding is discussed in relation to the aetiology of Eales' disease.

Adult↗
PubMed1989

Strain dependent & selective modulation of murine humoral immune response by carrageenan.

Carrageenan (CGN), a polygalactan extracted from red algae, induced 90 per cent suppression of antibody response to sheep red blood cells in Balb/C strain as compared to the untreated controls. Whereas the treatment failed to induce suppression in C57BL/6 strain. The observed suppression of antibody response was significant on all days tested (up to 40 days) and the suppression induced by CGN was real and not due to any direct effect on antigen or on the assay system followed. On the other hand, as evident from foot-pad thickness, the delayed type hypersensitivity (DTH) was unaltered in Balb/C strain after CGN treatment.

Animals↗
PubMed1987

Protective immunity induced by outer membrane proteins of Salmonella typhimurium in mice.

Outer membrane proteins (OMP) extracted from both smooth (C5) and rough (Rb2) strains of Salmonella typhimurium were able to induce protective immunity to salmonellosis. The OMP-induced protection lasted for at least 6 months. The antibody level was estimated by passive hemagglutination. In the C5 OMP-immunized mice, antibodies to both proteins and lipopolysaccharide were detected. On the other hand, in the Rb2 OMP-immunized mice, antiprotein but not antilipopolysaccharide antibodies were detected. Delayed-type hypersensitivity appeared as early as the second week after immunization with OMP and persisted through the fourth week.

Animals↗