Cell-mediated immunity in protection and pathology of malaria.

The stimulation of protective immunity against malaria is the goal of many research groups. But trials with antigens that stimulate antibodies have yet to fulfil these expectations, and it is increasingly recognized that non-antibody-mediated immunity is also important in immunity to malaria - especially through mediators such as gamma interferon, tumour necrosis factor and reactive forms of oxygen. However, the host can suffer if this type of immune response is too exuberant, and in this review, Ian Clark argues that much of what is recognized as clinical malaria is caused in this way. He suggests that only when discussed in these terms can malaria illness and pathology be seen as a coherent, predictable entity instead of a sea of unconnected surprises. Moreover, these ideas have important implications for vaccine development that, although requiring more basic work, must not be neglected.