Standardized horse antihuman lymphocyte globulin for clinical use.

This research article discusses the production and effectiveness of horse antihuman lymphocyte globulin in increasing the viability of skin grafts across diverse mammals.

Antithymocyte Membrane Serum Generation

• The paper begins by describing the method of creating the antithymocyte membrane serum. This was achieved by injecting horses multiple times with a fraction derived from human thymocytes—that is, lymphocytes developing in the thymus gland—combined with Freund’s adjuvant, a substance that enhances immune responses.
• The immune response of the horses led to the creation of the antithymocyte membrane serum, which showed immunosuppressive effects. These effects, which suppress the immune system’s response, were found in the γ2 region of the serum, which corresponds to a portion of the antibodies.
• The researchers also tried using the membrane-microsome fraction from lymphoblasts—which are immature white blood cells—for antigen, but discovered that this didn’t decrease the need for absorption.

Purification and Results

• The scientists used a purification process that combined QAE-Sephadex—a type of chromatography medium—and ammonium sulfate fractionation. This gave them pure γG-globulins—a type of antibody—in a good yield while reducing the presence of γ1-globulins
• The resulting antithymocyte membrane globulin was found to extend the longevity of skin allografts—transplants of skin from one individual to another—in cynomolgus monkeys, chimpanzees, and humans, thereby demonstrating its potential use in transplantations.
• No increase in antigenicity—immune response—over normal horse globulin was observed in the monkey test subjects.
• The globulin remained stable for up to two years when stored at a temperature of 4 degrees Celsius.

Clinical Trial

• The team produced a large batch (1.5kg) of antihymocyte membrane globulin, which is enough to potentially support 125 human cadaver renal (kidney) transplants.
• The globulin is being further evaluated in a controlled, concurrent, alternate clinical trial, in order to assess its real-world applicability and efficacy.