Q60. The first FDA-approved humanized monoclonal antibody, a…
Q60. The first FDA-approved humanized monoclonal antibody, adalimumab (Humira), resulted in a ∼ 12% incidence of a therapeutic problem in a small percentage of patients with rheumatoid arthritis. The problem was that they developed anti-therapeutic antibodies (ATA). This problem was subsequently reduced to ∼2–3% for patients receiving methotrexate which is a non-steroid anti-inflammatory and a mild immunosuppressant. What type of difference most likely led to the ATA response?
Read DetailsQ45. A Golden retriever (photo ‘A’) has cutaneous histiocyto…
Q45. A Golden retriever (photo ‘A’) has cutaneous histiocytosis, an inflammatory Lymphohistiocytic proliferative disorder that primarily involves skin and subcutis. Lesions may disappear spontaneously or regress and appear at new sites simultaneously. A biopsy of the skin (see photomicrograph ‘B’) reveals cells that are on IHC and express CD1, CD11c, MHC class II, CD4, and CD90. On transmission EM (see photomicrograph ‘C’), the tumor cells contain Birbeck granules comprised of antigen-bound Langerin (Langerin is a c-type lectin). Which of the following types of immune cells is most likely responsible for the inflammatory infiltrate in this dog?
Read DetailsQ61. A researcher is studying antibody diversity developing…
Q61. A researcher is studying antibody diversity developing in B cells. They observe that during V(D)J recombination, the enzyme terminal deoxynucleotidyl transferase (TdT) adds non-templated nucleotides at the junctions between gene segments. In which region of the antibody heavy chain is this junctional diversity most likely to directly affect the amino acid sequence?
Read DetailsQ38. Endogenous antigens, such as the viral proteins formed…
Q38. Endogenous antigens, such as the viral proteins formed within cells, are presented to CD8+ cytotoxic T cells via class MHC molecules. The MHC molecule visible to CD8+ T cells only has one variable chain. The variable chain needs another molecule to alter its conformation and help create a stable groove between its α1α2 domains. Without stabilization of the variable domain, viral peptides could not load onto the grove formed by the α1α2 component of the variable chain. Which molecule adjusts the 3-D structure of the variable chain of the MHC molecule visible to CD8+ T cells?
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