An innovative method of nonclinical efficacy and toxicological evaluation of recombinant Salmonella typhi Ty21a expressing HPV16 and 18 L1 proteins

Advancement in technology led to development of live attenuated Salmonella typhi Ty21a as enteric vector for expression of foreign proteins. Such vector platform is inevitable for development of vaccine candidate against human papilloma virus (HPV), the etiological agent of cervical cancer with high prevalence in developing nations. The high risk HPVs like type 16 and 18 contributes to 70% of cervical cancer, hence Indian Immunologicals Limited (IIL), Hyderabad, India developed a recombinant HPV vaccine by introducing HPV 16 and 18 L1 protein coding genes into attenuated S. typhi Ty21a vector. Being a genetically engineered enteric vector vaccine, it would be less expensive, with an ease of oral administration, instead of injectable that needs trained personale, is an added advantage for low socioeconomic setup compared to existing HPV vaccines. Establishing the nonclinical efficacy and safety/toxicity as per the national/international regulatory guidelines has become major constrain for such recombinant S. typhi HPV (rSt.HPV) vaccine. Since, the intended clinical mode of rSt.HPV is through oral route, whereas the live attenuated S. typhi • Current unconventional and innovative nonclinical testing procedures helps in exploring the alternate methods by pharmacologist/toxicologist. • Ultimately, such new drugs developed through technology must serve the humankind justifying the guidelines of regulatory agencies.