the first time you travel to a tropical region you may encounter the parasite that causes malaria for the first time. you forget to obtain anti-malaria drugs before you arrived and are bitten by an infectious mosquito. why is the adaptive immune response not helpful in protecting you against infection? lymphocytes of the adaptive immune system lack receptors to bind to novel antigens; exposure triggers these cells to express antigen-specific receptors but the process can take up to a week. the adaptive immune system utilizes phagocytosis to eliminate pathogens and this parasite is likely too large to be phagocytosed. the recognition and activation phases of the adaptive immune system take several days, during which time the infection could spread if the innate immune system cannot keep it in check the adaptive immune system can only respond to pathogens it has encountered before, it does not provide any defense or offer protection during the first exposure to the pathogen. the innate immune system suppresses the adaptive immune system while it is active to redirect cellular energy to, and improve the efficacy of, the innate defenses