Related Experiment Video
Updated: Apr 22, 2026
08:46
Author Spotlight: Investigating Bacteriophage-Induced Immune Responses in Gnotobiotic Mice
Published on: January 26, 2024
2.7K
The T4 molecule: function and structure
1Clinical Research Centre, Northwick Park Hospital, Harrow HAI 3UJ, and the Royal Postgraduate Medical School, Hammersmith, USA.
Immunology Today
|October 8, 2014
Summary
T4 antigen T lymphocytes are key immune regulators with diverse functions. Evidence suggests phenotypically distinct T4-positive T cell subpopulations perform these roles, with T4 potentially acting as a receptor for MHC class II and HTLV-III.
Area of Science:
- Immunology
- Cell Biology
- Virology
Background:
- T4 antigen T lymphocytes are central immunoregulatory cells.
- These cells exhibit helper/inducer functions, antigen proliferation, suppression control, and lymphokine release.
Purpose of the Study:
- To review evidence for distinct subpopulations of T4-positive T cells.
- To discuss the role of T4 as a receptor for MHC class II molecules and HTLV-III.
Main Methods:
- Literature review of immunological and cellular studies.
- Analysis of phenotypic differences in T4-positive T cell subpopulations.
Main Results:
- Growing evidence indicates phenotypically distinct subpopulations of T4-positive T cells.
- T4 is proposed as a potential receptor for class II MHC molecules.
- T4 is also discussed as a potential receptor for Human T-lymphotropic virus type III (HTLV-III).
Conclusions:
- T4-positive T cells are functionally diverse and composed of distinct subpopulations.
- The T4 molecule may serve as a receptor for both host (MHC class II) and viral (HTLV-III) ligands.
More Related Videos
Related Concept Videos
01:26DNA Bacteriophages
1.5K
Bacteriophages, or phages, are viruses that specifically infect bacteria, utilizing their genetic material to hijack host cellular machinery for replication. DNA bacteriophages employ single-stranded DNA (ssDNA) or double-stranded DNA (dsDNA) genomes. These phages exhibit diverse replication strategies and host interactions, influencing their ecological roles and applications in biotechnology and medicine.ssDNA BacteriophagesssDNA phages, with their small genomes, utilize unique strategies to...
1.5K
01:20Viral Replication: Lytic Cycle
2.9K
Bacteriophages, or phages, are viruses that specifically infect bacteria. Among them, T-even bacteriophages, such as T4, exhibit a well-characterized lytic replication cycle in Escherichia coli (E. coli). This process ensures the rapid proliferation of the virus while ultimately leading to the destruction of the bacterial host.Attachment and DNA InjectionThe infection process begins with the recognition and binding of the T4 phage to the E. coli cell surface. Tail fibers of the phage...
2.9K
01:30Lytic Cycle of Bacteriophages
59.8K
Bacteriophages, also known as phages, are specialized viruses that infect bacteria. A key characteristic of phages is their distinctive “head-tail” morphology. A phage begins the infection process (i.e., lytic cycle) by attaching to the outside of a bacterial cell. Attachment is accomplished via proteins in the phage tail that bind to specific receptor proteins on the outer surface of the bacterium. The tail injects the phage’s DNA genome into the bacterial cytoplasm. In the...
59.8K
00:43Lysogenic Cycle of Bacteriophages
49.4K
In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage. Some prophages can re-activate and enter the lytic cycle. This often occurs in response to a perturbation, such as DNA damage, but can also transpire in the absence of...
49.4K
01:16Viral Replication: Lysogenic Cycle
2.6K
The lysogenic cycle is a crucial viral replication strategy that allows bacteriophages to persist within host cells without immediately destroying them. This process is primarily observed in temperate phages, such as bacteriophage lambda (λ), which infects Escherichia coli. The cycle allows the viral genome to persist across bacterial generations while keeping host cells viable.Integration of the Viral GenomeUpon infection, bacteriophage lambda attaches to the bacterial surface and injects...
2.6K
01:16Transduction
2.9K
Among the three main modes of HGT—transformation, conjugation, and transduction—transduction is unique in that it is mediated by bacteriophages, or bacterial viruses.Transduction occurs in two ways. Generalized transduction occurs during the lytic cycle of a bacteriophage infection. In this process, bacteriophages infect bacterial cells, replicate within them, and ultimately cause cell lysis, releasing newly assembled virions. Occasionally, random fragments of the bacterial genome...
2.9K