<prompt> False statement about macrophages -Can harbor mycobacteriaDerived from blood monocytesInvolved in type III hypersensitivity reactionsProduce tumor necrosis factor and interleukins  <response>: Type III hypersensitivity occurs when there is an excess of antigen, leading to small immune complexes being formed that fix complement and are not cleared from the circulation. Large complexes can be cleared by macrophages but macrophages have difficulty in the disposal of small immune complexes. 