2014-10-24-世界卫生组织-WHO_BS_2014.2235_International_collaborative_study_to_evaluate_and_establish_the_1st_WHO_Reference_Reagent_for_Anti-Malaria_Plasmodium_falciparum_human_serum_40页_1mb

Summary of WHO Collaborative Study for First Anti-Malaria Human Serum Reference Reagent

Background

Malaria is a major global health threat, causing millions of deaths and infections annually. An urgent need exists for an immunoassay standard for anti-Plasmodium falciparum human serum antibodies to support vaccine development, harmonize immunological assays, and improve sero-epidemiological studies.

Reagent Development

A candidate reference reagent was developed from human serum samples collected from a malaria-endemic area in Kenya. After screening for specific antibodies and processing, including pooling, defibrination, and freeze-drying, it was stored at -20°C or lower. The preparation showed reactivity to multiple antigens, including AMA-1 and MSPs.

Collaborative Study

Sixteen laboratories from twelve countries participated in an international study using ELISA to evaluate the reagent's suitability. Key assessments included relative potency, stability under various temperatures, cross-reactivity with other antigens, and inter-laboratory comparability. Results indicated good agreement among labs when results were referenced to the candidate reagent.

Results and Proposal

The study confirmed that the candidate reagent has acceptable stability and is suitable for use as a reference standard. It is proposed that this preparation be established by the WHO Expert Committee on Biological Standardization (ECBS) in October 2014 as the first WHO Reference Reagent for Anti-Malaria (Plasmodium falciparum) human serum, with an arbitrary unitage of 100 units per ampoule.

Intended Uses

• Allow cross-comparisons of results from vaccine trials across different centers or products.
• Facilitate the standardization and harmonization of immunological assays used in epidemiology research.
• Optimize and validate immunological assays for malaria vaccine development.

Additional Findings

Stability tests showed the reagent maintains reactivity under elevated temperatures and after reconstitution, indicating long-term stability. Cross-reactivity studies revealed reactivity to pre-erythrocytic antigens, which is beneficial for studies on pre-erythrocytic vaccines. This reference reagent addresses the lack of standardized reagents in malaria research, particularly supporting the pre-clinical development of leading vaccine candidates like the RTS,S vaccine.

This proposal was agreed upon by participants and underscores the WHO's role in advancing global health through standardized biological reference materials.