Malaria causes tremendous early childhood morbidity and mortality, providing an urgent impetus for the development of a vaccine that is effective in neonates. However, the infant immune response to malaria may be influenced by events that occur well before birth. Placental malaria infection complicates one quarter of all pregnancies in Africa and frequently results in exposure of the fetus to malaria antigens in utero, while the immune system is still developing. Some data suggest that in utero exposure to malaria may induce immunologic tolerance that interferes with the development of protective immunity during childhood.
Malaria drug trials conducted in endemic areas face a major challenge in their analysis because it is difficult to establish whether parasitaemia in blood samples collected after treatment indicate drug failure or a new infection acquired after treatment. It is therefore vital to reliably distinguish drug failures from new infections in order to obtain accurate estimates of drug failure rates.
B‐cell and antibody responses to Plasmodium spp., the parasite that causes malaria, are critical for control of parasitemia and associated immunopathology. Antibodies also provide protection to reinfection. Long‐lasting B‐cell memory has been shown to occur in response to Plasmodium spp. in experimental model infections, and in human malaria.
Malaria is a major global health problem. Despite decades of research, there is still no effective vaccine to prevent disease in the majority of people living in malaria‐endemic regions. Additionally, drug treatment options are continually threatened by the emergence of drug‐resistant parasites. Immune responses generated against Plasmodium parasites that cause malaria are generally not sufficient to prevent the establishment of infection and can even contribute to the development of disease, unless individuals have survived multiple infections.
Developing efficacious vaccines for human malaria caused by Plasmodium falciparum is a major global health priority, although this has proven to be immensely challenging over the decades. One major hindrance is the incomplete understanding of specific immune responses that confer protection against disease and/or infection. While antibodies to play a crucial role in malaria immunity, the functional mechanisms of these antibodies remain unclear as most research has primarily focused on the direct inhibitory or neutralizing activity of antibodies.
Controlled human malaria infection (CHMI) is an established model in clinical malaria research. Upon exposure to Plasmodium falciparum parasites, malaria‐naive volunteers differ in dynamics and composition of their immune profiles and subsequent capacity to generate protective immunity. CHMI volunteers are either inflammatory responders who have prominent cellular IFN‐γ production primarily driven by adaptive T cells, or tempered responders who skew toward antibody‐mediated humoral immunity. When exposed to consecutive CHMIs under antimalarial chemoprophylaxis, individuals who can control parasitemia after a single immunization (fast responders) are more likely to be protected against a subsequent challenge infection.
The complexity of the Plasmodium parasite and its life cycle poses a challenge to our understanding of the host immune response against malaria. Studying human immune responses during natural and experimental Plasmodium infections can enhance our understanding of malaria‐protective immunity and inform the design of disease‐modifying adjunctive therapies and next‐generation malaria vaccines.
Plasmodium vivax infection, the predominant cause of malaria in Asia and Latin America, affects ~14 million individuals annually, with considerable adverse effects on wellbeing and socioeconomic development. A clinical hallmark of Plasmodium infection, the paroxysm, is driven by pyrogenic cytokines produced during the immune response. Here, we review studies on the role of specific immune cell types, cognate innate immune receptors, and inflammatory cytokines on parasite control and disease symptoms.
The epidemiology of febrile illness etiologies is under-explored in resource-poor settings. Establishing a local repertory of microorganisms circulating in blood of febrile and afebrile people is important for physicians. Blood was collected from 428 febrile and 88 afebrile children in Makokou (Gabon) and analyzed using polymerase chain reaction. Plasmodium spp. were the pathogens, which were most detected in febrile children (69.6%; 298/428) and in afebrile children (31.8%; 28/88) (P < 0.0001).
The recent reference genome assembly and annotation of the Asian malaria vector Anopheles stephensi detected only one gene encoding the leucine-rich repeat immune factor APL1, while in the Anopheles gambiae and sibling Anopheles coluzzii, APL1 factors are encoded by a family of three paralogs. The phylogeny and biological function of the unique APL1 gene in An. stephensi have not yet been specifically examined.