Page 1 of 1: h.influenza vaccination

decembermist · Credits: 41191 My Scrapbook

The initial vaccines against Haemophilus influenzae type B prepared with capsular polysaccharides were not very effective in children less than 2 years old. Subsequent vaccines have been greatly improved by the conjugation of the capsular polysaccharides to one of several proteins. Why does this conjugation improve immunogenicity?

A) CD4+ T lymphocytes are activated
B) Cytotoxic T lymphocyte responses are increased
C) Direct activation of B lymphocytes by the vaccine is increased
D) Nonimmune clearance of the vaccine is decreased
E) Phagocytosis of the vaccine is increased

decembermist · Credits: 41191 My Scrapbook

manpreet108 · Credits: 30682 My Scrapbook

The highly effective Hib conjugate vaccine, now routinely administered to infants and children, has dramatically reduced the prevalence of invasive Hib disease. The vaccine elicits a protective antibody and prevents disease by reducing pharyngeal colonization with Hib. Presently, no vaccines prevent disease caused by nontypeable H influenzae.

The first Hib vaccine was an unconjugated polysaccharide vaccine composed of the purified PRP capsular polysaccharide. This vaccine induced an ambiguous immune response, did not provide complete protection for children, and provided no antibody protection for infants. This led to the development of the conjugate vaccines in which PRP is covalently linked to a protein.

Currently, 3 licensed vaccines are available. They differ in the protein carrier used, the molecular size of the saccharide, and the method of conjugating the protein to the saccharide.
These include HibTITER (HbOC [mutant diphtheria toxin as the carrier protein]), PedvaxHIB (PRP-OMP [major outer membrane protein of Neisseria meningitidis serogroup B as the carrier protein]), and ActHIB/OmniHIB (PRP-T [tetanus toxoid as the carrier protein]).
PRP-OMP induces a good immune response after a single dose in infants, but antibody levels after 3 doses are lower than those induced by HbOC and PRP-T.

(PRP-OMP) combined with hepatitis B vaccine (Recombivax HB) is licensed for use at age 2 months, 4 months, and 12-15 months

thats some info on conjugate vaccine which i found useful.

can anyone ans the qn asked??

bhavu · Credits: 9481 My Scrapbook

although no refrence.this is solely logic but look to be rightto me.

here they are conjugated to protein.so same effect that protein bound drug undergo.

they can not be eliminated by kidney.
so non immune clearacne of kidney is reduced.
so i think d should be the answer.although comments are welcome.what is the answer given misty.

bhavu · Credits: 9481 My Scrapbook

hey i found it see harrison 15th edi page 781.

the mechanism of enhancement of immunogenicity is not well defined but release in part to the rendering of soluble antigens into a particulate form, the mobilization of phagocytes to the site of antigen deposition and the slowing down of the release of antigen,which prolongs stimulation of the immune response.

so i think it should be e.
sorry for wrong logic earlier.

manpreet108 · Credits: 30682 My Scrapbook

thanks bhavu for the reference...

so now we know that same adjuvant potentiation is also seen with other vaccines like diphtheria,TT toxoid,acellular pertussis vaccine,HBV.

pratik · Credits: 11374 My Scrapbook

yup bhavu is absolutely right on this

decembermist · Credits: 41191 My Scrapbook

thanks bhavu

		Sign In New User? Sign Up Sign in to access your control panel and messenger!
				TechZone \| SpiderNevi \| HowTo? \| Scrapbook!