Immunity in higher organisms can be broadly categorized into adaptive immunity and innate
immunity. Adaptive immunity is mediated by clonally distributed T and B lymphocytes which
provide immunological specificity and memory. In contrast, innate immunity is mediated by
the action of other cells such as macrophages and neutrophils, and traditionally has been
characterized as nonspecific. However, recent findings have shown that innate immunity has
some capacity for specific recognition. For example, insects, which lack the high level of …