Transmission-blocking activity is determined by transmission-reducing activity and number of control oocysts in Plasmodium falciparum standard membrane-feeding assay

详细信息    查看全文

• 作者：Kazutoyo Miura^a ; ¹ ; ^{kmiura@niaid.nih.gov" class="auth_mail" title="E-mail the corresponding author} ; Bruce J. Swihart^b ; ¹ ; ^{bruce.swihart@nih.gov" class="auth_mail" title="E-mail the corresponding author} ; Bingbing Deng^a ; ^{bingbing.deng@nih.gov" class="auth_mail" title="E-mail the corresponding author} ; Luwen Zhou^a ; ^{luwen.zhou@nih.gov" class="auth_mail" title="E-mail the corresponding author} ; Thao P. Pham^a ; ^{Phuong.pham2@nih.gov" class="auth_mail" title="E-mail the corresponding author} ; Ababacar Diouf^a ; ^{dioufa@niaid.nih.gov" class="auth_mail" title="E-mail the corresponding author} ; Timothy Burton^a ; ^{timothy.burton@nih.gov" class="auth_mail" title="E-mail the corresponding author} ; Michael P. Fay^b ; ^{mfay@niaid.nih.gov" class="auth_mail" title="E-mail the corresponding author} ; Carole A. Long^a ; ^{clong@niaid.nih.gov" class="auth_mail" title="E-mail the corresponding author}
• 关键词：TBV ; transmission-blocking vaccine ; SMFA ; standard membrane-feeding assay ; TRA ; transmission reducing activity ; % inhibition in oocyst intensity ; TBA ; transmission-blocking activity ; % inhibition in prevalence of infected mosquitoes ; DFA ; direct feed assay ; mo-contl ; observed mean oocyst intensity in the control group ; mt-contl ; true mean oocyst intensity in the control group ; ZINB model ; a zero-inflated negative binomial random effects model ; COM ; container of mosquitoes ; PR ; prediction region
• 刊名：Vaccine
• 出版年：2016
• 出版时间：29 July 2016
• 年：2016
• 卷：34
• 期：35
• 页码：4145-4151
• 全文大小：738 K

文摘

Malaria transmission-blocking vaccines (TBVs) are potentially helpful tools for malaria eradication. The standard membrane-feeding assay (SMFA) is considered one of the “gold standard” assays for TBV development. However, lack of consensus in reporting results from SMFA has made it very challenging to compare results from different studies. Two main readouts, % inhibition in mean oocyst count per mosquito (TRA) and % inhibition in prevalence of infected mosquitoes (TBA), have been used widely.

In this study, we statistically modeled the oocyst data in SMFA using data from 105 independent feeding experiments including 9804 mosquitoes. The model was validated using an independent data set that included 10,790 mosquitoes from 110 feeding studies. The model delineates a relationship between TRA, the mean oocyst count in the control mosquitoes (m_o-contl), and TBA. While TRA was independent from m_o-contl, TBA values changed depending on m_o-contl. Regardless of monoclonal or polyclonal antibodies tested, there were strong concordances between observed TBA and predicted TBA based on the model using m_o-contl and observed TRA. Simulations showed that SMFA with lower true control means had increased uncertainty in TRA estimates. The strong linkage between TBA, TRA and m_o-contl inspired creation of a standardized TBA, a model-based TBA standardized to a target control mean, which allows comparison across multiple feeds regardless of m_o-contl.

This is the first study showing that the observed TBA can be reasonably predicted by m_o-contl and the TRA of the test antibody using independent experimental data. This study indicates that TRA should be used to compare results from multiple feeds with different levels of m_o-contl. If a measure of TBA is desired, it is better to report standardized TBA rather than observed TBA. These recommendations support rational comparisons of results from different studies, thus benefiting future TBV development.