Anaplasma marginale in tick cell culture

Area of Science:

• Veterinary Entomology
• Microbiology
• Cell Biology

Background:

• Anaplasma marginale is an economically significant tick-borne pathogen.
• Establishing continuous cell cultures is crucial for studying tick-borne rickettsial organisms.

Purpose of the Study:

• To propagate Anaplasma marginale in a tick cell line.
• To characterize the growth and morphology of Anaplasma marginale in vitro.

Main Methods:

• Propagation of Anaplasma marginale in a Dermacentor variabilis embryonic cell line.
• Monitoring using transmission electron microscopy and indirect immunofluorescence with monoclonal antibodies.
• Continuous culture maintenance through multiple passages over extended periods.

Main Results:

• Three continuous Anaplasma marginale cultures were established from infected tick tissues.
• Organisms initiated growth near the nuclear membrane and formed cytoplasmic inclusions.
• Maximal growth occurred between 7-14 days, with new growth cycles initiated upon cell transfer.
• Morphology varied from erythrocyte-associated forms to midgut-like forms after several passages.

Conclusions:

• A tick cell line derived from Dermacentor variabilis embryos supports continuous Anaplasma marginale propagation.
• The established cell culture system provides a valuable tool for studying Anaplasma marginale.
• In vitro culture allows for observation of Anaplasma marginale's life cycle and morphological changes.