Jagdish C. Gupta

Gonadotropin-releasing hormone/human chorionic gonadotropin β based recombinant antibodies and vaccines

Gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) are unique targets for the control of fertility. Immunological approaches to neutralizing these hormones have additional utility in cancer treatment. Vaccines have been developed against both GnRH and hCG and these have undergone Phase I/II clinical trials documenting their safety, reversibility and efficacy. The heterospecies dimer hCG vaccine prevented pregnancy in women of proven fertility without impairment of ovulation or derangement of menstrual regularity and bleeding profiles. The protective threshold of antibody titers to achieve efficacy was determined in these first-ever trials. Recently, a recombinant vaccine against the beta subunit of hCG linked to the B subunit of heat labile enterotoxin has been made and expressed as a glycosylated conjugate in Pichia pastoris. Experiments indicate its ability to generate antibodies above the protective threshold in all immunized Balb/c mice. Ectopic expression of hCG/hCGbeta is observed in many advanced stage cancers of various origins. A chimeric high affinity and specific recombinant antibody against hCGbeta linked to curcumin kills hCGbeta expressing T lymphoblastic leukemia cells without any deleterious effect. Several synthetic and recombinant vaccines have been developed against GnRH. These reduce serum testosterone to castration levels causing atrophy of the prostate. Three Phase I/II clinical trials conducted in India and Austria have shown that these vaccines elicit non-surgical reduction of testosterone, a fall in prostate specific antigen and clinical improvement of prostate carcinoma patients. A multimer recombinant vaccine against GnRH has high efficacy for sterilization of pigs and other animals.

Mycobacterium indicus pranii is a potent immunomodulator for a recombinant vaccine against human chorionic gonadotropin

The objective of this work was to identify a human use-permissible adjuvant to enhance significantly the antibody response to a recombinant anti-hCG vaccine. Previous Phase II efficacy trials in sexually active women have demonstrated the prevention of pregnancy at hCG bioneutralization titers of 50ng/ml or more. Mycobacterium indicus pranii (MIP), a non-pathogenic Mycobacterium employed as an autoclaved suspension in aqueous buffer, significantly increased antibody titers in the FVB strain of mice. Three other genetic strains of mice: SJL, C3H, and C57Bl/6 responded with antibody titers several-fold higher than 50 ng/ml, which is the protective threshold in women, although there were differences in the peak titers attained. In addition, the duration of the antibody response was lengthened. The vaccine hCGβ-LTB, given together with MIP, induces both a Th1 and Th2 response, which is reflected in the production of not only IgG1, but also a high proportion of IgG2a and IgG2b antibodies.

Immunological Approaches Against Human Chorionic Gonadotropin for Control of Fertility and Therapy of Advanced-Stage Cancers Expressing hCG/Subunits

Citation Talwar GP, Gupta JC, Shankar NV. Immunological approaches against human chorionic gonadotropin for control of fertility and therapy of advanced‐stage cancers expressing hCG/subunits. Am J Reprod Immunol 2011; 66: 26–39

Priming with DNA Enhances Considerably the Immunogenicity of hCG β-LTB Vaccine.

Necessity to elicit antibody response above the protective threshold titres by sexually active women immunized to prevent pregnancy.

Making of a Unique Birth Control Vaccine against hCG with Additional Potential of Therapy of Advanced Stage Cancers and Prevention ofObesity and Insulin Resistance

Reviewed is the work which led to the development of a unique vaccine that prevents pregnancy in sexually active women without impairment of ovulation and block of their making normally their sex steroid hormones. Being given that hCG is not expressed by non-pregnant females, immunization with the vaccine is devoid of any crossreaction with any tissue of the body. It is totally reversible and women regained fertility on decline of antibodies. A recombinant vaccine has been developed which is highly immunogenic in mice. It is undergoing extensive toxicology under GLP conditions in rodents and a primate species, the marmosets, before resumption of clinical trials. Ectopic expression of hCG or its subunits takes place in a variety of cancers, particularly at advanced stage with adverse survival and poor prognosis. Anti-hCG antibodies exercise therapeutic action against such cancers as indicated by in vitro culture and in vivo studies in nude mice. Transgenic hCG β mice put on weight and manifest insulin resistance. Immunization of these mice with the recombinant hCG β-LTB vaccine prevents obesity and insulin resistance.

Development of a recombinant hCG-specific single chain immunotoxin cytotoxic to hCG expressing cancer cells.

A large number of cancers express human chorionic gonadotropin (hCG) or its subunits ectopically. Patients harboring such cancers have poor prognosis and adverse survival. PiPP is a monoclonal antibody of high affinity and specificity for hCGβ/hCG. Work was carried out to develop a PiPP based recombinant immunotoxin for the immunotherapy of hCG expressing cancers. Recombinant PiPP antibody was constructed in scFv format in which gene encoding the VH and VL domains were joined through a linker. This scFv gene was fused to the gene expressing Pseudomonas exotoxin (PE38), and cloned in a Escherichia coli based expression vector under the control of strong bacteriophage T7 promoter. Immunotoxin conjugating scFv(PiPP) and PE38, was expressed in E. coli as recombinant protein. Recombinant PiPP immunotoxin was purified from the bacterial cell lysate and tested for binding and killing of hCGβ expressing lymphoma, T-lymphoblastic leukemia and lung carcinoma cells in vitro. Immunotoxin showed nearly 90% killing on the cells. This is the first ever report on recombinant immunotoxin for binding and cytotoxicity to hCG expressing cancer cells, and thus can be a potential candidate for the immunotherapy of hCG expressing cells.

Advances in development of a contraceptive vaccine against human chorionic gonadotropin.

Introduction: There is continuing need for contraceptives. According to World Health Organization, 210 million pregnancies occur each year, out of which some 80 million are unintended. A vaccine offering privacy and periodic intake would be an attractive proposition. Areas covered: The article is a brief review of three vaccines developed against human chorionic gonadotropin (hCG) with progressively better attributes. Clinical trials have proven in more than one country the complete safety and reversibility of the anti-hCG vaccine(s) in women. Vaccination does not entail any disturbance in levels of reproductive tract hormones of the woman or any disturbance in menstrual regularity and bleeding profiles. Phase II clinical trials show the effective prevention of pregnancy in sexually active women of proven fertility. A recombinant vaccine amenable to industrial production has been developed; it induces substantially higher antibody titers in mice of four different genetic strains than those required to prevent pregnancy in women. Rigorous toxicology studies have been completed on this vaccine in rodents and marmosets. Expert opinion: This unique vaccine, requiring periodic intake and demonstrating no impairment of ovulation, hormonal profiles and menstrual regularity, is on the verge of final clinical trials under the aegis of the Indian Council of Medical Research and should be a valuable addition to the available contraceptives.

Immuno-interception of Fertility: Current Status of Vaccines Developed Against hCG and LHRH

Three vaccines against hCG have undergone successfully Phase I clinical trial but only one HSD-hCG vaccine went through Phase II efficacy trials demonstrating its ability to prevent pregnancy without impairment of ovulation and derangement of menstrual cycles and bleeding profiles. A semisynthetic vaccine against LHRH has had Phase I/II clinical trials in India and Austria in 28 patients of carcinoma prostate. Highlights of these vaccines are presented. Issues related to clinical trials are discussed.

Development of a potent invigorator of immune responses endowed with both preventive and therapeutic properties.

This article reviews briefly the making of an immunoprophylactic-cum-immunotherapeutic vaccine against leprosy. The vaccine is based on cultivable, heat-killed atypical mycobacteria, whose gene sequence is now known. It has been named Mycobacterium indicus pranii. It has received the approval of the Drug Controller General of India and the US Food and Drug Administration. Besides leprosy, M. indicus pranii has found utility in the treatment of category II (“difficult to treat”) tuberculosis. It also heals ugly anogenital warts. It has preventive and therapeutic action against SP2/O myelomas. It is proving to be a potent adjuvant for enhancing antibody titers of a recombinant vaccine against human chorionic gonadotropin, with the potential of preventing pregnancy without derangement of ovulation and menstrual regularity in sexually active women.

Making of a highly useful multipurpose vaccine

Reviewed briefly is the journey taken for development of an immunotherapeutic Vaccine for multibacillary leprosy. The nature of immune deficit in these patients is their inability to react to key antigens of M. leprae. Heterologous approach was adopted to identify a cultivable mycobacteria coded as Mw, now sequenced and named as Mycobacterium indicus pranii (MiP). MiP expediated bacterial clearance and shortened the recovery time of leprosy patients. It converted 65-70% of lepromin negative BL, LL patients to lepromin positivity status, which is not achieved by treatment with, drugs alone. The vaccine has received approval of The Drugs Controller General of India and USFDA and is being manufactured by M/s Cadilla Pharma. MiP is a potent invigorator of both cellular and humoral immune responses and has found many other useful applications. It is effective for treatment of Category II “difficult to treat” tuberculosis patients. In contrast to BCG, it is active in killed autoclaved form. It enhances considerably antibody titres to a potential birth control vaccine against hCG. It cures ugly anogenital warts. It has both preventive and therapeutic action against SP2/O Myelomas.