Establishment of an In Vitro Assay for Assessing the Effects of Drugs on the Liver Stages of Plasmodium vivax Malaria

AbstractAutoantibodies play an important role in the destruction of non-infected red blood cells (nRBCs) during malaria. However, the relationship between this clearance and ABO blood groups is yet to be fully enlightened, especially for Plasmodium vivax infections. Here we show that anti-RBC IgG and IgM are increased in anemic patients with acute vivax malaria. Furthermore, both antibodies are able to decrease the deformability of nRBCs, but only IgG can induce in vitro erythrophagocytosis. Such effects are enhanced in type O erythrocytes, suggesting that individuals from this blood group infected with P. vivax malaria may be more susceptible to develop anemia.

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Simple In Vitro Assay for Determining the Sensitivity of Plasmodium vivax Isolates from Fresh Human Blood to Antimalarials in Areas where P. vivax Is Endemic

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.1.170-173.2003 ◽

2003 ◽

Vol 47 (1) ◽

pp. 170-173 ◽

Cited By ~ 67

Author(s):

Bruce M. Russell ◽

Rachanee Udomsangpetch ◽

Karl H. Rieckmann ◽

Barbara M. Kotecka ◽

Russell E. Coleman ◽

...

Keyword(s):

Plasmodium Vivax ◽

Poor Response ◽

In Vitro Assay ◽

World Health ◽

Vitro Assay ◽

Malaria Clinic ◽

Drug Assays ◽

Tak Province ◽

Health Organization

ABSTRACT The aim of this study was to develop a simple, field-practical, and effective in vitro method for determining the sensitivity of fresh erythrocytic Plasmodium vivax isolates to a range of antimalarials. The method used is a modification of the standard World Health Organization (WHO) microtest for determination of P. falciparum drug sensitivity. The WHO method was modified by removing leukocytes and using a growth medium supplemented with AB+ serum. We successfully carried out 34 in vitro drug assays on 39 P. vivax isolates collected from the Mae Sod malaria clinic, Tak Province, Thailand. The mean percentage of parasites maturing to schizonts (six or more merozoites) in control wells was 66.5% ± 5.9% (standard deviation). This level of growth in the control wells enabled rapid microscopic determination (5 min per isolate per drug) of the MICs of chloroquine, dihydroartemisinin, WR238605 (tafenoquine), and sulfadoxine. P. vivax was relatively sensitive to chloroquine (MIC = 160 ng/ml, 50% inhibitory concentration [IC50] = 49.8 ng/ml) and dihydroartemisinin (MIC = 0.5 ng/ml, IC50 = 0.47 ng/ml). The poor response of P. vivax to both tafenoquine (MIC = 14,000 ng/ml, IC50 = 9,739 ng/ml) and sulfadoxine (MIC = 500,000 ng/ml, IC50 = 249,000 ng/ml) was due to the slow action of these drugs and the innate resistance of P. vivax to sulfadoxine. The in vitro assay developed in our study should be useful both for assessing the antimalarial sensitivity of P. vivax populations and for screening new antimalarials in the absence of long-term P. vivax cultures.

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A direct in vitro assay for evaluation of diphtheria vaccine efficacy. Measurement of the competition of toxin and toxoids for neutralizing antibodies

Immunology Letters ◽

10.1016/s0165-2478(97)88020-0 ◽

1997 ◽

Vol 56 (1-3) ◽

pp. 293-294

Author(s):

A Wahby

Keyword(s):

Vaccine Efficacy ◽

Neutralizing Antibodies ◽

In Vitro Assay ◽

Vitro Assay

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In Vitro Assay of Platelet Adhesiveness with Washed and Tanned Human Red Cells

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651281 ◽

1968 ◽

Vol 20 (03/04) ◽

pp. 384-396 ◽

Cited By ~ 1

Author(s):

G Zbinden ◽

S Tomlin

Keyword(s):

Platelet Adhesion ◽

Sodium Citrate ◽

Blood Platelets ◽

In Vitro Assay ◽

Red Cells ◽

Platelet Adhesiveness ◽

Vitro Assay ◽

In Vitro System ◽

Human Red Cells

SummaryAn in vitro system is described in which adhesion of blood platelets to washed and tannic acid-treated red cells was assayed quantitatively by microscopic observation. ADP, epinephrine and TAME produced a reversible increase in platelet adhesiveness which was antagonized by AMP. With Evans blue, polyanetholsulfonate, phthalanilide NSC 38280, thrombin and heparin at concentrations above 1-4 u/ml the increase was irreversible. The ADP-induced increase in adhesiveness was inhibited by sodium citrate, EDTA, AMP, ATP and N-ethylmaleimide. EDTA, AMP and the SH-blocker N-ethylmaleimide also reduced spontaneous platelet adhesion to red cells. No significant effects were observed with adenosine, phenprocoumon, 5-HT, phthalanilide NSC 57155, various estrogens, progestogens and fatty acids, acetylsalicylic acid and similarly acting agents, hydroxylamine, glucose and KCN. The method may be useful for the screening of thrombogenic and antithrombotic properties of drugs.

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