Prospects for hepatitis C vaccine.

Hepatitis C virus (HCV) is a major cause of chronic liver disease, cirrhosis and hepatocellular carcinoma worldwide. Unfortunately, neither a vaccine nor any effective therapy is available. Efforts are now directed towards the development of an effective vaccine besides chemotherapy. This review briefly summarizes the properties of an effective vaccine for the control of HCV infection. The mechanisms of protective immune response induced by HCV are not well understood. It is presumed that humoral and cellular immune responses play an important role. Even though there are various obstacles in the development of HCV vaccine, we describe a few promising approaches such as DNA vaccine, recombinant virus vaccine, HCV-like particles (HCV-LPs), peptide-based vaccine and plant-derived recombinant subunit vaccine.

Blood coagulation factor VIII: An overview.

Factor VIII (FVIII) functions as a co-factor in the blood coagulation cascade for the proteolytic activation of factor X by factor IXa. Deficiency of FVIII causes hemophilia A, the most commonly inherited bleeding disorder. This review highlights current knowledge on selected aspects of FVIII in which both the scientist and the clinician should be interested.

Pathogenesis of toxoplasmosis.

The present review article deals with the pathogenesis of toxoplasmosis. The article briefly highlights some important aspects such as different strains, mode of infection and clinical characteristics, entry into host cell, immune response, host parasite interaction, tissue cyst formation and disease recurrence.

Detection of circulating antigens by ELISA using penicillinase in sera of mice infected with Toxoplasma gondii.

An enzyme linked immunosorbent assay (ELISA) has been developed using penicillinase as an enzyme marker for the detection of Toxoplasma gondii antigens during the acute stage of infection in the sera of experimentally infected mice. Circulating antigens were detected as early as 2 days after the infection and all mice had antigenemia by fourth day. The developed ELISA test is sensitive, specific and reproducible.

ELISA using enzyme penicillinase for the detection of IgG antibodies to Trypanosoma evansi in sera of experimentally infected rabbits.

An Enzyme Linked Immunosorbent Assay (ELISA) using penicillinase as an enzyme marker has been developed for the detection of IgG antibodies in the sera of Trypanosoma evansi infected rabbits. Anti-T. evansi IgG antibodies were detected on 10th day after the infection and thereafter antibody titre rose progressively for 18 days. The developed assay is simple (end result assessed visually) and reproducible (4.4 and 14.0 percentage of intra and inter coefficient of variation respectively).

Assessment of enzyme linked immunosorbent assay based diagnostic kits (Toxokit-G and Toxokit-M) for the detection of IgG and IgM antibodies to Toxoplasma gondii in human serum.

An enzyme linked immunosorbent assay (ELISA) using penicillinase was developed in the form of diagnostic kits (Toxokit-G and Toxokit-M) for the detection of IgG and IgM antibodies to Toxoplasma gondii. The performance of both the kits was compared with commercially available diagnostic kits, i.e. Enzygnost-Toxoplasmosis/IgG (Behring Co., Germany), TOXOTEK-G (Flow Lab., U.K.) and Toxoplasma IgM Microassay (Diamedix Corp., U.S.A.) by testing toxoplasma-suspected human serum samples. The results indicate a good reliability between these diagnostic kits. Toxokit-G has 86.66 and 96.05% sensitivity and specificity respectively. The main advantage of Toxokit-G is that the end result can be assessed visually without using sophisticated instruments. Toxokit-M has 100% sensitivity and specificity and test results were not affected by the presence of antitoxoplasma IgG antibodies, rheumatoid factor or antinuclear antibodies.

Strip ELISA for the detection of IgG antibodies to Toxoplasma gondii.

An enzyme linked immunosorbent assay (ELISA) has been developed using a polycarbonate coated strip and penicillinase for the detection of IgG antibodies to T. gondii. Of 40 serum samples from patients clinically suspected to have toxoplasma infection, 24 were positive for IgG antibodies to T. gondii. Strip ELISA showed 95.83 per cent sensitivity and 89.4 per cent specificity. This method is simple (end result assessed visually), sensitive (detection of antitoxoplasma IgG antibodies to a level of 15 IU/ml) and reproducible (5.9 and 11.6 intra and inter percentage of coefficient of variation respectively).

Penicillinase as a potential enzyme marker for enzyme linked immunosorbent assay and its application in immunodiagnostics.

The present review article deals with the application of penicillinase in enzyme linked immunosorbent assay (ELISA) and describes the various characteristics of penicillinase. Using penicillinase as an enzyme marker, few kits have been developed to detect physiologically active proteins, infectious diseases and toxins. The review also highlights briefly the source of penicillinase, its production, isolation, purification and certain molecular properties.

Usage of penicillinase as an enzyme marker in enzyme linked immunosorbent assay for the detection of IgG antibodies to Toxoplasma gondii.

An Enzyme linked immunosorbent assay system has been developed using penicillinase as an enzyme marker for the detection of IgG antibodies to Toxoplasma gondii. This system is simple (end result assessed visually) reliable (the results are matching with other available commercial ELISA based kit), sensitive (detection of antitoxoplasma IgG antibodies to a level of 15 IU/ml) and reproducible (4.3 & 6.7% intra and inter coefficient of variation respectively). Experimental results with human serum samples using our system has shown consistent results and were in total agreement with other commercially available diagnostic kits. It is therefore suggested that ELISA system using penicillinase can be a simple, sensitive and reliable method for the diagnosis of toxoplasmosis in human.

Detection of toxoplasma IgM antibodies by ELISA method: a comparative study of different enzymes as markers.

Detection of toxoplasma IgM antibodies by employing enzyme linked immunosorbent assay (ELISA) technique was developed using different enzymes viz, horseradish peroxidase (HRP) (EC. 1.11.17), urease (EC. 3.5.15) and penicillinase (EC 3.5.2.6) as markers. Of these enzymes, HRP is light sensitive and needs dark chamber, also inactivated by preservative sodium azide. Similarly urease test system is extremely pH sensitive and demands special care during ELISA technique. Whereas penicillinase showed certain distinct advantages viz. stable at room temperature, high specific activity and economical. In the present studies it was observed that the sensitivity of penicillinase is similar to HRP and urease, marker enzymes used in commercially available diagnostic kit. The prominent feature of detection of toxoplasma IgM antibodies involving these three enzymes are: a) Shorter incubation time (About 2.5 hours) b) No false positive reaction. Moreover, these enzyme conjugates were prepared from F (ab')2 fragments of antitoxoplasma rabbit serum to elicit specific interaction with IgM antibodies only, avoiding cross interaction with other non-specific proteins like compliment systems and rheumatoid factor.

Efficacy of various anthelmintics against third-stage larvae of Ancylostoma caninum in the brain of mice.

In an experimental larval infection of Ancylostoma caninum in mice, the efficacy of various anthelmintics against the larvae migrated and established in the brain is reported for the first time. Albendazole and flubendazole were the most effective drugs. Thiabendazole, benacil, phenacizole, oxfendazole and mebendazole showed significant larvicidal activity. Tetramisole, levamisole, fenbendazole, Sch 18099, pyrantel pamoate, morantel tartrate and oxantel pamoate did not show any significant activity even at relatively high dose levels.

The efficacy of some newer broad spectrum anthelmintics against third-stage larvae of Ancylostoma caninum in the mouse.

The efficacy of eight anthelmintics against Ancylostoma caninum larvae in the skeletal muscles of mice was evaluated. Levamisole (5 X 40 mg/kg), thiabendazole (5 X 400 mg/kg), oxfendazole (5 X 100 mg/kg), albendazole (5 X 100 mg/kg), flubendazole (5 X 200 mg/kg), benacil (5 X 200 mg/kg) and phenacizole (5 X 200 mg/kg) showed marked larvicidal activity (98 to 99%). Sch 18099 did not show larvicidal activity even at 5 X 400 mg/kg.

Serum protein profile of mice during infection with of Ancylostoma caninum and after the administration of tetramisole and levamisole.

Serum protein changes in mice following Ancylostoma caninum larval infection were observed as decrease in albumin, gamma globulin and increase in beta globulin. These serum protein components showed a tendency to return back to their normal levels after the administration of effective anthelmintic such as tetramisole or levamisole to the infected mice. The increased level of beta globulin after treatment although decreased but did not return to its normal level within 14 days observation period.

Host immune response against homologous challenge infection of Ancylostoma caninum larvae after application of effective anthelmintics.

The development of immunity against Ancylostoma caninum larval reinfection has been investigated in mice after the primary infection has been treated with an effective anthelmintics. Experimentally A, caninum larvae infected mice treated with levamisole (5 x 40 mg/kg), thiabendazole (5 x 200 mg/kg), oxfendazole (5 x 100 mg/kg), or albendazole (5 x 100 mg/kg) when challenged with A. caninum larvae showed 47.77 to 55.81% larval reduction from the challenge dose indicating thereby the development of partial immunity.