Retroviral transfer of T-cell receptor genes produces cells with a broad range of lytic activity

R J Orentas1, L A Bircher, S Roskopf

  • 1Department of Pediatrics, Section of Hematology-Oncology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.

The ability to transfer the T-cell receptor (TCR) for antigen using a retroviral vector has opened the door to a new paradigm for T-cell-based immunotherapy. Using recombinant TCRs, a population of activated T cells can now be redirected to recognize and lyse cellular targets according to the specificity afforded by the transduced TCR genes. To examine the range of lytic activity displayed by the transduced TCRs, transduced T cells were re-cloned by limiting dilution and quantitatively analysed for lytic activity. The lytic activity of the transduced TCRs varied considerably, as determined by the Km and Vmax of lysis. The lytic activity seen in the secondary clones generated from vector-transduced peripheral blood mononuclear cell demonstrated that one of the clones approached the lytic activity of the parental 'TCR donor' cytotoxic T-cell lymphocyte (CTL) clone, whereas the remainder demonstrated either reduced Vmax or reduced Vmax and Km. Thus, the lytic activity of a transduced TCR depends not only on its genetic sequence but also on the cellular context within which it is expressed. Analysis of TCR Vbeta transcript levels by real time polymerase chain reaction revealed that while total Vbeta gene expression was fairly constant, expression of the retrovirally transduced Vbeta chain varied greatly in transduced CD8+ CTL clones.

Related Concept Videos

Size and Structure of Viral Genomes01:26

Size and Structure of Viral Genomes

Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
Retrovirus Life Cycles01:10

Retrovirus Life Cycles

Retroviruses have a single-stranded RNA genome that undergoes a special form of replication. Once the retrovirus has entered the host cell, an enzyme called reverse transcriptase synthesizes double-stranded DNA from the retroviral RNA genome. This DNA copy of the genome is then integrated into the host’s genome inside the nucleus via an enzyme called integrase. Consequently, the retroviral genome is transcribed into RNA whenever the host’s genome is transcribed, allowing the retrovirus to...
Retroviruses02:33

Retroviruses

Retroviruses and retrotransposons both insert copies of their genetic elements into the genome of the host cell. Thus, the viral genes are passed on when the host genome is replicated or translated. A typical retroviral DNA sequence contains 3-4 genes that encode the different proteins required for its structural assembly and function as a molecular parasite. This DNA is transcribed into a single mRNA, which is very similar in structure to conventional mRNAs, i.e., it is capped at the 5’...
Immune Response Against Viral Pathogens01:29

Immune Response Against Viral Pathogens

The immune system's response to viral infections is a complex and coordinated process involving natural killer (NK) cells, T cell-mediated responses, and antibody-mediated responses.
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...
LTR Retrotransposons03:08

LTR Retrotransposons

LTR retrotransposons are class I transposable elements with long terminal repeats flanking an internal coding region. These elements are less abundant in mammals compared to other class I transposable elements. About 8 percent of human genomic DNA comprises LTR retrotransposons. Some of the common examples of LTR retrotransposons are Ty elements in yeast and Copia elements in Drosophila.
The internal coding region of LTR retrotransposons and their mechanism of transposition closely resembles a...
Cytotoxic T Cells-mediated Immune Response01:27

Cytotoxic T Cells-mediated Immune Response

Cytotoxic T cells are a vital component of the immune system. They have the remarkable ability to identify and target antigens on infected or abnormal cells. These antigens often originate from intracellular pathogens such as viruses or abnormal proteins cancer cells produce.
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...