Same amount of IgM produced in primary as in secondary. IgG production increased - predominant antibody for secondary response, may remain elevated for extended period of time (esp. if antigen in from of vaccine or natural infection ) check this for accuracy? *When attempting to answer if an immune response is primary or secondary you are trying to answer if this is the *first time you have been exposed to the antigen or NOT. (this is not the same as 1 st 2 nd , and 3 rd line defense) If question asks about what line of defense is being utilized, remember that the physical barriers of the Innate/Natural immune system are first, and 2 nd is the Inflammatory system and lastly the adaptive immune systems are recruited for assistance.
Aging and the Immune System o T-cell Immune function decreases d/t changes in lymphocyte function o Decreased T-cell activity d/t decrease thymus size o Decreased B-cell function d/t decrease in antibody production in response to antigenic challenge, increases in circulating immune complexes and in circulating autoantibodies (antibodies against self-antigens) o Shift in the balance of T-cell subsets is observed. These changes may result in increased susceptibility to infection. Fetal and Neonatal immune function Stage of Development Immune Function Differences Fetal antibody production deficient -Last trimester, fetus capable of producing a primary immune response (IgM only), but is unable to produce a significant IgG response – Active transport facilitates the passage of maternal antibodies into the fetal circulation (d/t size of immunoglobulin, unable to diffuse across cellular layer) Neonate At birth, total IgG levels in umbilical cord= adult levels, but when cord severed, antibody titers begin to drop The maternal antibodies are slowly catabolized after birth until they disappear altogether by about 10 months of age. The neonate begins producing IgG at birth, & the child’s antibodies reach protective levels after about 6 months of age.
Inflammation ( AKA. Second line of defense ) Key Player Role and Function Mast Cell “I simply want you to know that mast cell degranulation also triggers the activation of the acute phase reactants” . (quote from his lecture notes) Mast cell degranulation results in the release of four main items: (these are acute phase reactants) histamine, cytokines, leukotrienes, & prostaglandins ) Histamine is responsible for causing vasodilation , it increases vascular permeability , (* sound like sepsis ) it increases blood flow to the site of injury which ultimately causes erythema and swelling at the site of injury Histamine 1 (PRO) Pro-inflammatory -Present on smooth muscle- especially bronchi (causes muscle to contract= Broncho restriction) Histamine 2 (ANTI) Anti-inflammatory (suppresses leukocyte function) -Found on parietal cells of stomach mucosa and induces secretion of gastric acid as part of normal physiology of the stomach Cytokines Cytokines can react quickly or may be more delayed. IL 4 is
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- Fall '15