Ferreira M
Department of Parasitology, University of São Paulo, Brazil.
Immunol Cell Biol. 1996 Aug;74(4):301-5. doi: 10.1038/icb.1996.54.
Recent population-based efficacy trials of the synthetic malaria vaccine SPf66 have shown restricted, if any, clinical protection against Plasmodium falciparum infection. Despite the well-established role of antibodies in effector responses against asexual blood-stage malaria parasites, the titres of anti-SPf66 IgG antibodies do not correlate with the ability of sera from vaccine recipients to inhibit parasite growth in vitro nor with partial clinical protection which could be detected in some trials. Qualitative or functional parameters of SP66-induced antibody responses, such as IgG subclass composition and affinity, may be more predictive of clinical protection against malaria than quantitative estimates of antibody concentration or titre. Since these parameters are readily estimated by laboratory techniques currently available, and may be modulated by changes in vaccination protocols and by the use of different adjuvants, a better understanding of qualitative antibody responses induced by SPf66 and other asexual blood-stage malaria vaccine candidates, and of their relationship with clinical protection in vivo, is urgently needed for the improvement of currently used immunization schedules.
近期基于人群的合成疟疾疫苗SPf66有效性试验表明，其对恶性疟原虫感染的临床保护作用有限（若有作用的话）。尽管抗体在针对无性血液期疟原虫的效应反应中已确立的作用，但抗SPf66 IgG抗体滴度与疫苗接种者血清在体外抑制寄生虫生长的能力不相关，也与在某些试验中可检测到的部分临床保护作用不相关。SP66诱导的抗体反应的定性或功能参数，如IgG亚类组成和亲和力，可能比抗体浓度或滴度的定量估计更能预测对疟疾的临床保护作用。由于这些参数可通过现有实验室技术轻易估计，并且可能因疫苗接种方案的改变和使用不同佐剂而受到调节，因此迫切需要更好地了解SPf66和其他无性血液期疟疾候选疫苗诱导的定性抗体反应，以及它们与体内临床保护的关系，以改进目前使用的免疫程序。
