Question 1
The IgG molecules which cross the placenta and circulate in a baby's bloodstream provide the baby with natural (active/innate/passive) immunity.Question 2
Discuss the importance of there being two types of adaptive immune responses (antibody and cell-mediated).Answer 1
passiveAnswer 2
Pathogens (and other hazards to the body) vary in type and form. Many pathogens are extracellular parasites while others are intracellular parasites. Large numbers of pathogens are bacteria, and others are eukaryotes. The two different immune responses are effective at targeting different types of antigens. Cell-mediated immunity is directed against endogenous antigens, and therefore intracellular parasites. The antibody immune response primarily targets exogenous antigens and is therefore largely effective against extracellular pathogens. Antibody functions are particularly effective against bacteria. Antibodies can also neutralize non-living hazards like toxins. Consequently, the adaptive immune response against a specific pathogen will primarily involve one or the other type. The immune response is unlikely to be completely one-sided in all infections. For example, an intracellular parasite may produce a toxin, so while a cell-mediated immune response will kill infected cells and slow the spread of the pathogen, neutralizing antibodies directed against the toxin will limit the damage done by the toxin.