The Role of Immunity in Fighting and Checking the Spread of Viral Diseases

Immunology is truly a fascinating discipline that meets the challenge and offers opportunity in fighting and checking the spread of diseases. Many viruses infect humans. The host response to invading virus depends upon the infectious agents and where it is encountered. In response to virus entry there may not be, always, an overt reaction leading to clinical manifestation. There may be simply, subclinical infection, which would protect the individual from later exposure. A number of specific immune effector mechanisms together with non-specific defence mechanism play role in eliminating an infective virus.

Viruses are intracellular parasites. Many viruses have developed very effective escape mechanisms. Influenza virus which has acquired various types of antigens associated with their capsids. The outer envelope of influenza virus has numerous spikes, which are linked to pathogenicity and antigenicity of the strain. Gene recombinations cause antigenic shifts, producing new strains. Certain viruses like rubella causing measles produce immunosuppressive chemicals. Varicella zoster and a number of herpes virus groups, which replicate in the upper respiratory tract, remain latent in the sensory ganglia of spinal and cranial nerves. In these places the viruses do not come in contact with antibodies, hence remain protected. Epstein- Barr virus has Complement receptor 2 (CR2), Influenza virus has Sialic residue on cell surface glycoprotein, Rhinovirus contains Intracellular adhesion molecule( ICAMs ) and Vaccinia virus with Epidermal growth factor receptor C for virus entry. The fact that antibody protects against some virus infection is attested by the widespread use of immunoglobulin for prophylaxis against measles, and by the world wide efforts made to stimulate antibody production by immunization against poliomyelitis viruses.

Keywords: Intraepithelial neoplasia(CIN); Tumor antigen-specific cytotoxic T lymphocyte (CTL); G-CSF (Granulocyte colony-stimulating factor); Human papillomavirus (hrHPV); Cytomegalovirus (CMV); Complement receptor 2 (CR2); Intracellular adhesion molecule( ICAMs )