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Activation of Ras is key for lymphocyte development and function. The understanding of Ras activation in T cells now takes an important step forward by the initial analysis of mice lacking the Ras activator RasGRP.
The HIV-AIDS epidemic in Africa is now of epic proportions. This has precipitated a crisis in public health that needs to be resolved in a uniquely African way. Local and Western research efforts must be blended with strong political and social will to get the preventative message and appropriate therapies to the people whom need them most.
It is becoming more apparent that some B cells do not carry the same antigen receptors throughout their life. B cells that have edited their receptors have now been found in humans as rare cells that accumulate in arthritic joints.
The complement inflammatory cascade is crucial to our innate ability to ward off infection. Two papers now provide evidence linking C5 and C3a to murine airway hyperresponsiveness, a partial model of human asthma. Surprisingly, these complement proteins appear to have opposite effects.
T cell activation usually requires TCR engagement by antigen and another, costimulatory, signal. Modeling studies now indicate that this second signal may only slightly enhance TCR signaling, but nevertheless results in an exponential increase in cell numbers.
