The complete second signal for B cell activation requires which of the following interactions?

The complete second signal for B cell activation requires which of the following interactions?
 
  A) CD40-CK40L interaction
  B) cytokine-cytokine receptor interaction
  C) TH-B cell interaction
  D) All of these are necessary.

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Which of the following roles do B cells play?
 
  A) antigen presentation
  B) antigen processing
  C) antigen uptake
  D) antigen presentation, processing, and uptake

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Communication between cells of the immune system is accomplished in many cases through
 
  A) allelic exclusion.
  B) clonal deletion.
  C) cytokines.
  D) allelic exclusion, clonal deletion, and cytokines.

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Chemokines are a group of small proteins that
 
  A) attract T cells to sites of injury.
  B) function as chemoattractants for phagocytes and lymphocytes.
  C) potentiate specific immune responses.
  D) attract T cells, phagocytes, and lymphocytes, as well as potentiate specific immune responses.

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Which of the following is involved in B cell selection and tolerance?
 
  A) clonal anergy
  B) clonal deletion
  C) clonal anergy and deletion
  D) allelic exclusion