Memory B-cell responses against merozoite antigens after acute Plasmodium falciparum malaria, assessed over one year using a novel multiplexed fluorospot assay by Jahnmatz, P, Sundling, C, Yman, V, Widman, L, Asghar, M, Sondén, K, Stenström, C, Smedman, C, Ndungu, F, Ahlborg, N, Färnert, A