Malaria Antigens

Plasmodium Antigen Products by Targets

Unusual features of Plasmodium Fig.1 Unusual features of Plasmodium

Parasite entry into and replication within red blood cells Figure.2 Parasite entry into and replication within red blood cells

Plasmodium is a genus of parasitic alveolates. It was first described in the year 1885 and now contains about 200 species including several species that can cause malaria in their natural hosts. Plasmodium parasite always has two hosts in its life cycle: a dipteran insect host (for example, mosquitos) and a vertebrate host. Plasmodium can perform sexual reproduction in their definitive host. The life cycle of Plasmodium species involves some different stages in both the two kinds of hosts, including sporozoites, merozoites, gametocytes and hypnozoites in some species. Five Plasmodium species are known to regularly infect humans (P. falciparum, P. malariae, P. ovale, P. vivax and P. knowlesi).

The life cycle of Plasmodium species involves several different stages in the insect and vertebrate hosts. Plasmodium parasites exist in the salivary gland of infected mosquitoes as sporozoite form. Sporozoites are injected into the vertebrate host along with the saliva when the infected mosquito bites the vertebrate host. The sporozoites join in the blood stream and then are transported to the liver, where they invade and replicate within liver cells (or hepatocytes). Newly produced parasite (merozoite form) return to the blood and start to invade red blood cells. Merozoites grow first to a ring-shaped form and then turn to a larger trophozoite form. Trophozoites then mature to schizonts which divide several times to produce new merozoites. The infected red blood cells eventually burst, allowing the newly produced merozoites return back to the blood and invade new red blood cells. Most merozoites continue this replicative cycle while some of them differentiate into male or female sexual forms called gametocytes. These gametocytes exist in the blood circling system until a mosquito feeds on the infected vertebrate host, taking up them along with the blood. Gametocytes develop into male and female gametes in the salivary gland of infected mosquitoes and form a zygote. Zygotes will finally develop into sporozoites and continue the life cycle.

Rapid diagnostic tests for malaria have been developed based on the detection of malarial antigens present in peripheral blood. Most tests use monoclonal antibodies and detect particular malarial antigens in blood specimens. Tests have been developed to detect antigens, including histidine-rich protein 2 (HRP-2), aldolase, lactate dehydrogenase (LDH), etc.

  1. Merozoite Surface Protein (MSP)—MSP-1 is synthesized at the very beginning of schizogony, or asexual merozoite reproduction. The merozoite first attaches to a red blood cell using its MSP-1 complex. The MSP-1 complex targets spectrin, a complex on the internal surface of the cell membrane of a red blood cell. MSP2 may play a role in the merozoite attachment to the erythrocyte.
  2. Circumsporozoite protein (CSP)-- The circumsporozoite protein is the immunodominant surface antigen on the sporozoite (the infective stage of the malaria parasite that is transmitted from the mosquito to the vertebrate host).
  3. Histidine Rich Protein 2 (HRP-2)--Histidine-rich protein II (HRP2) is a naturally occurring histidine- and alanine-rich protein localized in several cell compartments including the cytoplasm of P. falciparum. It is found as concentrated packets in the host erythrocyte cytoplasm and on the infected erythrocyte membrane.
  4. Lactate dehydrogenase (LDH)-- Lactate dehydrogenase (LDH) is an intracellular enzyme, which catalyses the readily reversible reaction involving the oxidation of lactate to pyruvate with nicotinamide adenine dinucleotide (NAD) serving as coenzyme. The lactate dehydrogenase enzyme from P. falciparum (PfLDH) has been considered as a potential molecular drug target.
  5. Aldolase --Aldolase has been implicated as a protein coupling the actomyosin motor and cell surface adhesins involved in motility and host cell invasion in the human malaria parasite Plasmodium falciparum.

With years of protein and antigen production experience, Creative Diagnostics now can provide a wide range of Plasmodium antigens with high-quality and cheaper price to support various biological programs, including Plasmodium Aldolase, P. falciparum Circumsporozoite protein, P. vivax MSP-1 protein, etc. Welcome to contact us for quotation and more details.

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