Lymphocyte transformation test in veterinary clinical immunology

Area of Science:

• Veterinary Immunology
• Laboratory Animal Science

Background:

• The lymphocyte transformation test (LTT) is crucial for evaluating animal immunologic competence.
• Assessing lymphocyte function and identifying mitogenesis-suppressing factors in serum are key diagnostic challenges.

Purpose of the Study:

• To detail the methodology and interpretation of the LTT for assessing animal immune status.
• To highlight the utility of LTT in detecting impaired lymphocyte function and serum-based immunosuppression in animals.

Main Methods:

• Utilized lymphocyte transformation measured by thymidine incorporation in media with autologous, homologous, or fetal calf serum.
• Employed multiple phytomitogens (concanavalin A, pokeweed mitogen, phytohemagglutinin) at optimal and decreased concentrations.
• Analyzed background counts and stimulation indexes (SI) in various animal species.

Main Results:

• Optimal results achieved using at least two, preferably three, phytomitogens.
• Established baseline background counts and stimulation indexes for healthy dogs, cattle, and horses.
• Correlated increased background counts with viral infections and lymphoreticular disorders; decreased counts with various diseases.
• Observed increased SI during disease incubation and decreased SI linked to immunosuppressive factors, reduced lymphocyte responsiveness, or unidentified serum factors.

Conclusions:

• The LTT is a valuable tool for diagnosing immunologic disorders in animals.
• Specific patterns of background counts and stimulation indexes can indicate different disease states and underlying causes of immune dysfunction.