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In vitro maintenance of Leishmania amastigotes directly from lesions: advantages and limitations
1Biology Department, Fairfield University, Connecticut 06430, USA.
Abstract:
Leishmania amazonensis (MHOM/BR/77/LTB0016) amastigotes were obtained from mouse cutaneous lesions and maintained in vitro for 48 hr at pH 4.6, 33 C. These organisms were reproducing, capable of transformation to promastigotes, and did not display the promastigote-specific antigen, GP46. In contrast, 97% of the organisms maintained for 24 hr at 31 C, pH 7.3, were positive for GP46. Thus, short-term cultivation of this L. amazonensis strain under appropriate conditions can provide a high yield of amastigotes for various in vivo and in vitro studies. However, the possible interference of host immunoglobin on the surface of these amastigotes needs to be considered because fluorescent-labeled anti-mouse immunoglobulin was detected on 16% of lesion-derived amastigotes even after 114 hr of cultivation.
Insights
Cultivating Leishmania amazonensis amastigotes under specific conditions yields viable organisms for research. However, host immunoglobulin may interfere with surface antigen detection in these parasites.
Area of Science:
- Parasitology
- Molecular Biology
- Immunology
Background:
- Leishmania amazonensis amastigotes are the intracellular stage of the parasite responsible for leishmaniasis.
- Maintaining amastigotes in vitro is crucial for studying parasite biology and developing treatments.
- The promastigote-specific antigen GP46 is a key marker for distinguishing life stages.
Purpose of the Study:
- To establish optimal in vitro cultivation conditions for Leishmania amazonensis amastigotes.
- To assess the viability and characteristics of cultivated amastigotes.
- To evaluate the potential interference of host factors in amastigote studies.
Main Methods:
- Leishmania amazonensis amastigotes were isolated from mouse lesions.
- Organisms were cultured in vitro at different pH and temperature conditions (pH 4.6, 33°C vs. pH 7.3, 31°C).
- Amastigote viability, transformation capacity, and GP46 antigen expression were assessed. Host immunoglobulin presence was detected using fluorescent-labeled anti-mouse immunoglobulin.
Main Results:
- Amastigotes cultured at pH 4.6 and 33°C for 48 hours showed reproduction and transformation potential but lacked GP46.
- In contrast, 97% of amastigotes cultured at pH 7.3 and 31°C for 24 hours were GP46 positive.
- Host immunoglobulin was detected on 16% of lesion-derived amastigotes even after 114 hours of cultivation.
Conclusions:
- Short-term cultivation of Leishmania amazonensis under specific conditions can yield a high number of amastigotes for research.
- Careful consideration of cultivation parameters is necessary to ensure amastigote purity and accurate antigen analysis.
- The presence of host immunoglobulin on amastigotes requires attention when interpreting in vitro and in vivo experimental results.