[Study of adoptive immunotherapy with lymphokine-activated killer (LAK) cells and interleukin-2 for metastatic renal cell carcinoma. I. Generation of LAK cells by incubation in serum-free medium]

Long-term in vitro culture of Plasmodium vivax isolates from Madagascar maintained in Saimiri boliviensis blood

Background

Plasmodium vivax is the most prevalent human malaria parasite and is likely to increase proportionally as malaria control efforts more rapidly impact the prevalence of Plasmodium falciparum. Despite the prominence of P. vivax as a major human pathogen, vivax malaria qualifies as a neglected and under-studied tropical disease. Significant challenges bringing P. vivax into the laboratory, particularly the capacity for long-term propagation of well-characterized strains, have limited the study of this parasite’s red blood cell (RBC) invasion mechanism, blood-stage development, gene expression, and genetic manipulation.

Methods and results

Patient isolates of P. vivax have been collected and cryopreserved in the rural community of Ampasimpotsy, located in the Tsiroanomandidy Health District of Madagascar. Periodic, monthly overland transport of these cryopreserved isolates to the country’s National Malaria Control Programme laboratory in Antananarivo preceded onward sample transfer to laboratories at Case Western Reserve University, USA. There, the P. vivax isolates have been cultured through propagation in the RBCs of Saimiri boliviensis. For the four patient isolates studied to-date, the median time interval between sample collection and in vitro culture has been 454 days (range 166–961 days). The median time in culture, continually documented by light microscopy, has been 159 days; isolate AMP2014.01 was continuously propagated for 233 days. Further studies show that the P. vivax parasites propagated in Saimiri RBCs retain their ability to invade human RBCs, and can be cryopreserved, thawed and successfully returned to productive in vitro culture.

Conclusions/significance

Long-term culture of P. vivax is possible in the RBCs of Saimiri boliviensis. These studies provide an alternative to propagation of P. vivax in live animals that are becoming more restricted. In vitro culture of P. vivax in Saimiri RBCs provides an opening to stabilize patient isolates, which would serve as precious resources to apply new strategies for investigating the molecular and cellular biology of this important malaria parasite.

Electronic supplementary material

The online version of this article (10.1186/s12936-017-2090-7) contains supplementary material, which is available to authorized users.

Bioprocess development for the cultivation of human T-lymphocytes in a clinical scale

Adoptive transfer of large numbers of donor-derived T-lymphocytesmay offer a promising treatment of a variety of viral and malignant diseases. The key step in this approach is the ex vivo generation of sufficient quantities of these cells in a short time.We have investigated the influence of several important cultivation parameters on the proliferation of human T-lymphocytes to develop a large-scale fermentation process usingdifferent types of stirred bioreactors. Such systems offer manypotential advantages over the static culture systems commonlyused today.Peripheral blood mononuclear cells of healthy but CMV positive donors were stimulated with monoclonal antibodies (anti-CD3 and anti-CD28) and Interleukin-2. The influence of osmolality, Interleukin-2 concentration, pH, oxygen tension, feeding strategyand temperature on T-cell proliferation was investigated and theoptimised conditions were transferred to a novel stirred suspension bioreactor with an especially designed magnetic stirrbar to minimize the shear force (working volume 550 ml) and a standard stirred vessel (working volume 1000 ml).Preferable conditions for the cultivation of primary T-lymphocytes were an osmolality of 276-330 mOsmol kg(-1),an Interleukin-2 concentration of 100 U ml(-1), a pH rangeof 7.0 to 7.3, an oxygen tension of 5-50% and a temperature of 38.5 degrees C. After 238 h of cultivation 2.8 x 10(9) cells in the stirred vesseland 1.5 x 10(9) cells in the suspension bioreactor were obtained with a percentage of T-cells >94%. The specificity of the cells wasmaintained during cultivation as proven by IFN-gamma secretionafter exposure to a hCMV protein.