Biopolymer Xanthan: A New Adjuvant for DNA Vaccines

Abstract DNA vaccines have been evaluated as an option to prevent several diseases. In this study, the capacity of the xanthan biopolymer to improve the DNA vaccines immune response, administered intramuscularly, was evaluated. The experimental vaccines consisted of genes encoding fragments of the proteins LigA and LigB of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Copenhageni strain Fiocruz L1-130. The humoral immune response was evaluated by indirect ELISA. Cytokine expression levels were determined by RT-qPCR. Compared to the control group, the IgG antibody levels of animals immunized with pTARGET/ligAni and pTARGET/ligBrep plasmids associated with xanthan biopolymer were significantly higher than the control group. Additionally, there was a significant increase in IL-17 expression in animals vaccinated with pTARGET/ligBrep and xanthan.

HPV & HPV vaccination: Issues in developing countries.

Cervical cancer is the second-most common cancer in women worldwide causing most cancer related deaths in women in developing countries including India. The most predominant etiological factor for cervical cancer is persistent infection of certain high-risk types of human papillomaviruses (HR-HPVs), while low-risk types are associated with benign cervical lesions and genital warts. In India, the most common (98%) oncogenic types are HPV types 16 and 18 with HPV 16 exclusively (80-90%) prevalent. Two recently developed virus-like particle (VLP) based prophylactic HPV vaccines, quadrivalent Gardasil (HPV 16/18/6/11) and Cervarix (HPV 16/18) offer great promise. Several other therapeutic vaccines are also in clinical trials and are yet to establish their efficacy. The use of already developed VLP vaccines in resource-poor regions is limited by several factors, most importantly the high cost of the vaccine. Therefore efforts are being made in India to develop cost-effective second-generation vaccines. Besides cost, there are several socio-cultural and ethical issues involved with the implementation of already developed vaccines including the acceptability of HPV vaccination by preadolescent girls and their parents in India.

Fundamental study of expression-library immunization against Taenia taeniaeformis in rats.

Expression-library immunization has been proposed as an effective means to screen a large number of genes of the pathogen as candidate protective molecules. In this study, we examined the efficacy of expression-library immunization using a T. taeniaeformis rat model system. Total RNAs were isolated from the last 15 segments of adult T. taeniaeformis and poly A RNA was purified. cDNA library was produced using SuperScript Plasmid System, which contains a mammalian expression vector, pCMV*SPORT6. From about 3,500 clones examined, more than 800 clones were found to contain DNA fragments. About 200 clones were sequenced and the homology search was carried out. The blast search revealed that 29% of the expression genes were mitochondrial genes (rRNA; 17%, protein; 12%). Nuclear rRNA genes (10%), nuclear protein (9%) and genes from Escherichia coli were also detected. Forty-two percent of sequences did not show a significant similarity to any genes deposited in the public database. Rats were immunized with expression-library and injected orally with 1,000 T. taeniaeformis eggs. However the protective effect of expression-library vaccine was not confirmed.