Which of the following is/are subunit vaccines:

Ans. is 'a' i.e. Typhoid Vi, 'b' i.e. H. influenza vaccine (Hib), 'c' i.e. Hepatitis B vaccine Subunit vaccines (cellular fraction) Subunit vaccines are defined as those containing one or more pure or semipure antigens. o Instead of entire microbe, subunit vaccine include only the antigens that best stimulate the immune system. Subunit vaccines are obtained from extracted cellular fraction which is the major antigenic constituent of organism. o Examples are: (i) Meningococcal vaccine from cell wall polysacchlaride (ii) Pneumococccal vaccine from Capsular polysaccharide (iii) Hepatitis B polypeptide vaccine (iv) Typhoid vaccine from Vi polysaccharide (v) H. Influenza vaccine from capsular polysaccharide.