Measles and the two vaccination shots given to ensure the child will Essay

Measles and the two vaccination shots given to ensure the child will never catch Measles - Essay Example Another unique feature of AAI is that it improves upon repeated exposure (Levinson and Jawetz 353). Vaccines are preventive agents that contain viral molecules to activate the AAI, so that when the virus is encountered in the environment, large amounts of specific antibodies are already present to act against it. Both humoral and cell-mediated immunity play a role in developing AAI (Levinson and Jawetz 353). This writing tries to explain the reasons behind the timing and the number of dosages of vaccines, particularly measles and diphtheria-pertussis-tetanus vaccines. In particular, basics on immune response and immunization are provided, before a detailed discussion on vaccines is given. Although their mechanisms are different, innate immunity and AAI interact with each other for optimal response against a potential infection. The non-specific innate immunity is responsible for the engulfment of foreign molecules by macrophages or other antigen-presenting cells (APC) like dendritic cells and B cells (Levinson and Jawetz 357-359). Upon phagocytosis of foreign bodies, AAI then ensues when these APCs expose the engulfed antigens to their surfaces through class II major histocompatibility complex (MHC) membrane proteins. The antigen-MHC complex then binds with an antigen-specific receptor on the surface of a helper T lymphocyte, initiating the release of interleukins (IL) that stimulates the maturation of many immune cells (Levinson and Jawetz 359). In turn, the activated helper T cells initiate the release of interleukins (IL), particularly IL-2, which initiates antigen-specific T-cell growth and activates cytotoxic T cells, IL-4, which promotes growth of B cells, and IL-5, which allows activation of B-cells. IL-4 and IL-5 also induce the transformation of IgM to IgG, IgA and IgE. In effect, it stimulates clonal expansion of both T and B cells after exposure with specific antigens. Cytotoxic T cells, in particular,