10-06-2006, 07:05 AM
A 5-year-old boy with a history of reccurrent ear infections receives his preschool booster immunization against diphtheria-tetanus-pertussis. He is participating in a community-sponsored study to determine the humoral immune response to tetnus toxoid (tt). His response is well below normal for age- and sex-matched children. Peripheral B lymphocyte count and T lymphocyte count and function are within the reference range. The antibody he makes is possitive in both the passive hemagglutination and complement-mediated lysis of tt-coated erythrocytes. His antibodies do not opsonize tt-coated latex particles for phagocytosis and do not directly precipitate tt efficiently. This child most likely has a defect in which of the following processes?
A) Affinity maturation of immunoglobulins
B) Immunoglobulin isotype switching
C) Recommbination of heavy chain variable region genes
D) Recombination of light chain variable region genes
E) Somatic mutation of immunoglobulin genes
A) Affinity maturation of immunoglobulins
B) Immunoglobulin isotype switching
C) Recommbination of heavy chain variable region genes
D) Recombination of light chain variable region genes
E) Somatic mutation of immunoglobulin genes
)how is it going?????