22 Nov : The first session on the second day of the conference began with the discussion by Dr Dinkar Salunke from the National Institute of Immunology on ‘structural basis of antigen specificity’. This session was chaired by Dr Samir Brahmchari.
Dr Salunke started the talk by defining the immune defense as specificity of molecular recognition to discriminate self against non-self and Antigen recognition as physiological processes of self-nonself discrimination.
The question which he wanted to address during the talk was ‘How do germline antibodies, which have not seen any antigen a priori, address such a wide range of antigen specificities?’
The recognition of non-self components require diverse specificities as the pathogens/antigens are adept at changing ‘shape’-after being ‘recognized’ and pathogens disguise as self after recognition. The antigens that need to be recognized are infinite in comparison to the number of germline antibodies that can be made through genetic recombination is limited ~108. So nowadays a new concept is being worked out i.e. “One antibody – many antigens” which implies that conformational flexibity in the antigen can recognize different antibodies. The antibody diversity can be generated by Genetic recombinations (generating diverse receptors), Conformational flexibility (generating diverse structures), Ag-Ab juxtapositions (generating diverse binding mode).
Thermodynamic analysis indicated that germ line antibodies exhibit potential for multiple conformational states. CD and NMR analyses have indicated flexible nature of the antigen. Dr Saulanke suggested that the humoral response against the antigens can be enhanced in the body by molecular mimicary by the antibodies as in case of the anti-sugar and anti-peptides against sugar antigens.
Dr Salunke summarized the talk by suggesting that diverse germ-line antibodies, each exhibiting several discrete structures, can show diverse binding modes leading to generation of antibody diversity. Economic utilization of the conformational repertoire, designed to minimize probability of self-re-activities and methods to counter antigenic variation should be adopted.
GENETIC LANDSCAPE OF INDIA AND FUTURE OF MEDICINE
The next discussion was taken up by Prof Samir K. Brahmachari from Council of Scientific & Industrial Research, New Delhi. He talked about the ‘Emerging Areas of Biomedical Research’ under the topic genetic landscape of India and future of medicine.
In this discussion Prof Brahmachari laid emphasis on development of ‘synthetic biology’ as a tool to develop newer medicines to treat genetic diseases. The successful sequencing of the complete human genome and development of the draft of 3.2 billion nucleotide sequences of the human genome leads to a challenge of new millennium to unravel the function and the meaning of the sequences so that we can use it to discriminate against people, and also to save them from deadly diseases like Cardiovascular disorder, Metabolic syndrome, Diabetes, Infectious disorders, High altitude disorders, Asthma, Susceptibility to malaria &tuberculosis.
India shows the largest study carried out on genomic variation representing the vast ethnic and linguistic diversity of India vis-a-vis disease candidate genes. It was realized (in 1997) that the rich Genetic resource of India could be used for population polymorphism scanning instead of gene knockout studies in model organisms to understand the link between sequence and function. This can provide an aid for future design of drugs, drug response, as well as genotype –phenotype correlation studies. It is only now that the potential of the rich and diverse genetic wealth of India is beginning to be realized for genomic research and predictive medicine for healthcare for tomorrow.
The role of DNA Polymorphisms in complex disorders has been identified and Genotype – Phenotype correlation for predictive medicine have been developed as in case of response of salbutamol in asthmatic patients in India. Prof Brahmachari summarized by predicting that the next decade will see emergence of technologies such that 100,000 plus human genome can be completely sequenced in a fraction of the present cost, every possible animal, insect genome sequences will be available, whole genome expression profile of all possible tissues under various developmental conditions will be available, Bacterial and lower eukaryotic genome sequences will allow us to design organism to carry out specific function (Synthetic Biology).
“What we do with our newfound knowledge is in the hands of society, but the responsibility to use it prudently rests with us.”
EMERGING AREAS OF BIO-MEDICAL RESEARCH
The third session began with the discussion on immunology by Dr S.K. Basu from National Institute of Immunology, New Delhi under the topic ‘Microbial Infections, vaccines and public health. This session was chaired by Dr Sujit Bhattacharya. Dr Basu started the talk by discussing about the common man’s perceptions and exceptations from this discipline and the realities of microbiological infections, vaccines and public health especially in country like ours. The utility of vaccination came into being with eradication of small pox and now resentment is also appearing for not having vaccines for AIDS and SARS or birth control.
According to Dr. Basu certain limitations are there for effective long term public health measures because of various reasons like complete vaccination of whole population is not possible, infections are caused by plethora of related organisms and pathogens can revolve due to vaccine pressure