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Updated: Aug 16, 2026

Quantification of Intracellular Growth Inside Macrophages is a Fast and Reliable Method for Assessing the Virulence of Leishmania Parasites
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Quantification of Intracellular Growth Inside Macrophages is a Fast and Reliable Method for Assessing the Virulence of Leishmania Parasites

Published on: March 16, 2018

Promotion of leishmanial infections in non-permissive host macrophages by conditioned medium

E Handman, C L Greenblatt

    Zeitschrift Fur Parasitenkunde (Berlin, Germany)
    |September 21, 1977
    PubMed

    Insights

    Conditioned medium from Leishmania enriettii enhances infection in mouse macrophages, suggesting a soluble factor is involved. This factor is specific to L. enriettii and can be neutralized by antibodies.

    Area of Science:

    • Parasitology
    • Cell Biology
    • Immunology

    Background:

    • Leishmania enriettii infects guinea pig macrophages but not mouse macrophages in vitro.
    • Understanding host-pathogen interactions is crucial for controlling leishmaniasis.

    Purpose of the Study:

    • To investigate the factors influencing Leishmania enriettii infection in different macrophage types.
    • To identify potential soluble mediators involved in Leishmania enriettii pathogenesis.

    Main Methods:

    • Culturing Leishmania enriettii and Leishmania tropica in guinea pig and mouse macrophages.
    • Preparing and applying conditioned medium from Leishmania cultures to macrophages.
    • Utilizing immune precipitation with anti-Leishmania serum to neutralize conditioned medium effects.

    Main Results:

    • Conditioned medium from L. enriettii cultures significantly promoted L. enriettii infection in mouse macrophages at both 37°C and 32°C.
    • Conditioned medium from L. tropica cultures did not enhance L. enriettii infection in mouse macrophages.
    • Immune precipitation of the conditioned medium with anti-Leishmania serum abolished its enhancing effect on infection.
    • Homologous conditioned medium enhanced L. tropica infections in guinea pig macrophages, though quantification was challenging.

    Conclusions:

    • A soluble factor present in L. enriettii conditioned medium is responsible for promoting its infection in mouse macrophages.
    • This factor appears to be specific to L. enriettii and is sensitive to antibody neutralization.
    • The findings suggest a novel mechanism of host-pathogen interaction in leishmaniasis, mediated by parasite-derived soluble factors.

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