Viable leukocyte intracellular components (VLIC)

Viable leukocyte intracellular components, often referred to in the context of dialyzable leukocyte extracts or transfer factors, represent a complex mixture of low-molecular-weight molecules derived from the cytoplasm of white blood cells. These components are not a single molecular target but rather a therapeutic preparation intended to modulate the immune system by transferring antigen-specific cell-mediated immunity from a sensitized donor to a naive recipient. Historically, these extracts have been investigated for their ability to enhance the immune response against viral, fungal, and bacterial infections, as well as serving as adjuvant therapy in certain malignancies and primary immunodeficiency disorders. Because the term describes a heterogeneous collection of intracellular substances rather than a specific protein, enzyme, or receptor, it is generally classified as a biological product or complex mixture rather than a discrete therapeutic target. Its clinical use is often limited by challenges in standardization, characterization of active ingredients, and the emergence of more specific recombinant immunotherapies.

Other names

Leukocyte lysateDialyzable leukocyte extractTransfer factor

The mechanism involves the transfer of delayed-type hypersensitivity and cell-mediated immunity from an immune donor to a non-immune recipient through low-molecular-weight dialyzable molecules, potentially modulating T-cell activity and cytokine expression.