Innate and Adaptive Immunity Assignment Example | Topics and Well Written Essays - 1250 words

Innate and Adaptive Immunity - Assignment Example   IgG antibodies appear after a longer period and then remain in the bloodstream permanently, providing protection against re-infection (New Jersey Department of Health, 2011). In view of this, quarantine should be imposed on the patient if the IgM antibodies are present. This would mean that this is a case of the first infection. Otherwise, the patient should not be quarantined. IgG antibodies can be present in blood because of vaccination (Lab Tests Online, 2012). Question 2 A secondary infection occurs when a pathogen attacks an organism whose immune system is weak due to an earlier infection. Secondary responses result from the stimulation of B cells. The clonal expansion theory has three key areas: specificity, memory, and tolerance. Specificity comes about since the production of antigen-specific antibody is in response to triggering of antigen-reactive clones. Memory is because subsequent responses to an antigen are stronger than the initial one. Tolerance is because of the destruction of self-reactive B and T cells. When an antigen with multiple epitopes gains enters the body, different clones of B cells recognize and produce antibodies against the different epitopes. The pathogens have antigens on their surface. Antibody response to protein antigen actively involves T cells and B cells. Since CD4 T lymphocytes stimulate B cells, they are known as helper T cells. Cytotoxic T cells kill other cells that virus-infected, allografts or cancer cells. Helper T cells secrete cytokines. Cytokines provide amplification mechanism by proliferation and differentiation (stimulation of B cell clonal expansion). They also determine the type of antibodies produced (Sridhar, 2012). Question 3 Human immunodeficiency virus (HIV) attacks a protein, CD4, on helper T cells of the immune system and associated with it. These cells are the immune system’s main infection-fighting cells. T helper cells are necessary for the activation of B-cells and cytotoxic T-cell immu ne responses. During this time, the body cannot make antibodies properly. Destruction of infected cells cannot occur without helper T-cells. Production of antibodies occurs in an effort to fight the virus. An HIV blood test is one that detects HIV antibodies. The body produces antibodies in response to HIV antigen. Therefore, in as much as the virus is destroying the helper T cells, the body continues to produce antibodies to fight the virus. These are the antibodies detected in an HIV antibody test. A negative result on a blood test means that either the person is not infected or that one is infected, but production of antibodies has not occurred. This is because, after the initial infection, it takes time for the body to produce antibodies. Seroconversion is the process of conversion from antibody negative to antibody positive blood (Melbourne Sexual Health Centre, 2007). Question 4 Innate immunity exists prior to antigenic exposure while adaptive immunity develops in response to antigen exposure. For adaptive immunity, resistance develops with repeated exposure to antigen, but for innate immunity, repeated exposure has no effect on resistance. Innate immunity is not specific to any antigen. The adaptive response, on the other hand, is antigenic specific. This means the ability to respond in a quickly during re-exposure to a pathogen (University of Arizona, 2008).