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Few studies have been done on engineered antibodies for diagnosis of tospovirus infections. The present study was undertaken to develop a single-chain variable fragment (scFv) for specific diagnosis of infection by groundnut bud necrosis virus (GBNV), the most prevalent serogroup IV tospovirus in India. Heavy chain (372 nucleotide [nt]) and light chain (363 nt) variable region clones obtained from a hybridoma were used to make an scFv construct that expressed a ~29-kDa protein in E. coli. The scFv specifically detected GBNV in field samples of cowpea, groundnut, mung bean, and tomato, and it did not recognize watermelon bud necrosis virus, a close relative of GBNV belonging to tospovirus serogroup IV. This study for the first time demonstrated the application of a functional scFv against a serogroup-IV tospovirus.

Foot-and-mouth disease (FMD) is a transboundary animal disease caused by foot-and-mouth disease virus. In India, systematic preventive vaccination using inactivated trivalent (O, A and Asia 1) vaccine is the strategy being adopted to control FMD. The use of non-structural protein (NSP)-contaminated inactivated vaccine raises concerns over differentiation of infected and vaccinated animals (DIVA) by NSP based immunoassays. However, 2C being a membrane associated protein usually remain absent in vaccine formulations and thus, anti-2C response is one of the most reliable indicator of the FMDV infection. In this study, 34 amino acids from N-terminus of 2C protein were removed to eliminate membrane-binding amphipathic helicase activity for the expression of recombinant protein in soluble form. Truncated 2C (2Ct) was utilized for development of an indirect ELISA (I-ELISA) for bovine and the developed 2Ct I-ELISA was validated using a panel constituting of serum of naïve, vaccinated and infected animals. The assay was compared with the in-house r3AB3 I-ELISA and the overall concordance was 85.31%. The diagnostic sensitivity and specificity of the 2Ct I-ELISA were 92.9% and 94.0%, respectively. The apparent prevalence of anti-2C antibodies for random bovine samples tested by the developed assay was 23.7%. The developed ELISA will help in augmenting the sensitivity of detection if used in combination with r3AB3 I-ELISA for sero-surveillance., (Copyright © 2013 Elsevier B.V. All rights reserved.)

To aid the clinical diagnosis of typhoid fever in India, where most hospitals and primary health centres have no facilities for culture, we report on the development of a novel and rapid immunodiagnostic kit for the direct detection of Salmonella Typhi--specific IgG antibodies against S. Typhi flagellar H antigen. The disease often does not show a specific clinical picture, and can be confused with other febrile illness such as malaria, dengue fever and Staphylococcus aureus. To overcome the problem of cross reactivity specific epitope of the flagellar H antigen was immobilised on the testing kit strip eliminating chances of cross reactivity and false positive results thereby increasing the specificity of the test. Since the immunodiagnostic kit, uses the flagellar H antigen from bacteria present in our country, the antibodies present in the serum of patients of our country will have maximum binding affinity, enhancing the sensitivity of our test kit. The immunodiagnostic kit on analysis gave a positive result with clinically diagnosed typhoid positive patient serum and negative results were obtained with the sera of clinically diagnosed malaria, abscess of Staphylococcus aureus and Visceral leishmaniasis (Kala-azar) patients.

Background & Objective: Definitive diagnosis of kala-azar requires demonstration of parasites by diagnostic protocols based on invasive organ aspirations. We evaluated in the present study the diagnostic utility of an immunochromatographic test (ICT) for detection of anti- rK-39 antibodies for the non-invasive diagnosis of kala-azar and post kala-azar dermal leishmaniasis (PKDL) at a tertiary care centre of north India., Methods: The study was conducted in the Department of Microbiology, All India Institute of Medical Sciences, New Delhi, from July 2003 to October 2004. Of the 120 samples tested, 57 were found to be positive by ICT; of which, 51 were diagnosed as kala-azar and 6 as PKDL. The controls included individuals from endemic (50) and non endemic (19) areas with malignancies, haemolytic disorders, chronic liver diseases, hypersplenism, portal hypertension, metabolic disorders and sarcoidosis. In addition, 47 sera from confirmed cases of tuberculosis, malaria, typhoid, filariasis, leptospirosis, histoplasmosis, toxoplasmosis, invasive aspergillosis, amoebic liver abscess, AIDS, leprosy, cryptococcosis, strongyloidiasis, cyclosporosis, patients having collagen vascular diseases and hypergammaglobulinaemia were also tested to check the specificity of the test., Results: Of the 51 cases with kala-azar 43 were males, children accounted for 25 per cent of these cases. All had fever of duration ranging from <1 month to 1.5 yr (median 4.5 months). All PKDL patients (n=6, 4 males) gave a history of having suffered from kala-azar in the past, and their slit skin test smears were microscopically positive for Leishman-Donovan (LD) bodies. The strip test was positive in all the cases of kala-azar and PKDL (estimated sensitivity 100%), all control sera were negative by the ICT (specificity 100%)., Interpretation & Conclusion: The rK-39 ICT is a highly sensitive and specific test, and may be suitable for a rapid, cost-effective and reliable field diagnosis of kala-azar and PKDL.

The article focuses on the Indian initiative of making kits for diagnosis of various infectious and non-infectious diseases as well as reproductive hormones and hormones in various other endocrine disorders. Indigenous diagnostic kits for the detection of various infections such as filariasis, typhoid, amebiasis, Japanese encephalitis, hepatitis, HIV, dengue, leishmaniasis, malaria, rabies, toxoplasmosis, rotavirus, and group A streptococci have been developed. Agreements to transfer the know-how of some of these leads to industries have been signed. The know-how of enzyme-linked immunosorbent assay (ELISA) for detection of hepatitis C has been successfully transferred to industry and is being commercially produced. For detection of HIV-1 and HIV-2, indigenous diagnostic kits based on three different formats, namely ELISA, Western blot and rapid test have been developed and are being commercially produced by Indian industries. The factors influencing the successful transfer of laboratory-scale diagnostic assays from academia to industry and their commercial exploitation have been discussed. Indian scientists have made seminal contributions in exploring the possibility to develop an effective and safe contraceptive vaccine to control the increasing human population of India. Achieving contraception by means of vaccine is a novel approach, which entails generation of a specific antibody response against antigens critically involved in the process of mammalian reproduction. In India, three major programs on contraceptive vaccines based on the beta-subunit of human chorionic gonadotrophin ((beta)hCG) for women, ovine follicle stimulating hormone (oFSH) for men, and riboflavin carrier protein for both males and females have been initiated. The work at the National Institute of Immunology, New Delhi on contraceptive vaccine for women, based on (beta)hCG, has demonstrated, for the first time, that it is feasible to regulate fertility by such an approach. Basic research being carried out to achieve immunocontraception by interfering at sperm-oocyte interaction level has been briefly discussed. These developments are still at the research stage. In addition to advances in the area of contraceptive vaccines, a non-steroidal contraceptive oral pill has been developed by Central Drug Research Institute, Lucknow, commercially produced by two Indian pharmaceutical companies and has been incorporated in the National Family Welfare Program. Another interesting approach for fertility regulation in male has been developed in India, which involves vas occlusion with styrene maleic anhydride (SMA) and is currently undergoing clinical trials in human subjects.

Although the definitive diagnosis of diseases caused by worms and protozoa depends upon the demonstration of adult parasite or its ovum in excreta, blood and tissue biopsies of the patient, immunological methods can be of help in the identification of associated immunological syndromes, pathogeneses of these infections in man and as a guide to therapy. However, the non-availability of pure antigens is a limiting factor in effective application of these tests. The present paper describes the immunological syndromes associated with these diseases as well as some of the in-use immunodiagnostic tests.