Context
Recently, researchers explored the use of CAR-T cell therapy to combat Human Immunodeficiency Virus, with a recent study showing that genetically engineered immune cells suppressed the virus in two patients for one and two years without daily medication, raising hopes for a potential functional cure.
1. The Mechanism: CAR-T Cell Therapy for HIV
- The Process: T-cells (immune soldiers) are extracted from a patient’s blood and genetically engineered to become “living drugs”.
- The Modification: For HIV, these cells were given “dual features”: they were programmed to better find/kill infected cells and engineered with a protective “armor” to prevent the HIV virus from infecting the T-cells themselves.
2. Current Global HIV Landscape
- Scale: Approximately 40 million people are living with HIV globally.
- Treatment Limitations: While current antiretroviral drugs make HIV a manageable chronic disease, the virus hides in “reservoirs” in the body and rebounds immediately if treatment is stopped.
- The Goal: Moving beyond daily drug adherence to long-lasting viral suppression through gene and cell therapy.
3. About CAR-T Cell Therapy (Chimeric Antigen Receptor T-cell)
- Chimeric antigen receptor (CAR) T-cell therapy is a revolutionary, personalized form of immunotherapy that modifies a patient’s own immune cells (T cells) to recognize and kill cancer cells. It is primarily used to treat certain advanced blood cancers, such as leukemias, lymphomas, and multiple myeloma, especially when other treatments have failed.
- Process:
- Collection: T cells are collected from the patient’s blood.
- Genetic Modification: T cells are engineered in the lab to produce Chimeric Antigen Receptors (CARs) that target cancer cells.
- Expansion: Millions of modified CAR-T cells are grown in the laboratory.
- Infusion: The engineered CAR-T cells are infused back into the patient.
- Targeting: CAR-T cells identify and destroy cancer cells inside the body.
4. B- Cell vs T-Cell
| Feature | B Cells | T Cells |
| Site of Maturation | Bone Marrow | Thymus |
| Type of Immunity | Humoral Immunity (targets pathogens in bodily fluids) | Cell-Mediated Immunity (targets infected or cancerous cells) |
| Antigen Recognition | Recognizes and binds to antigens directly | Requires antigens to be “presented” by other cells via MHC molecules |
| Primary Function | Produce and secrete antibodies | Coordinate the immune response (Helper T) or kill infected cells (Cytotoxic T) |
| Life Span | Generally shorter-lived (except for memory cells) | Often longer-lived; can circulate for many years |
Consider the following statements regarding CAR-T cell therapy and Human Immunodeficiency Virus:
1. CAR-T cell therapy involves genetically modifying a patient’s T cells to target diseased cells.
2. HIV primarily attacks B cells responsible for antibody production.
3. In CAR-T therapy, engineered T cells are expanded in the laboratory before being infused back into the patient.
4. T cells are associated with cell-mediated immunity, while B cells are associated with humoral immunity.
Which of the statements given above are correct?
(a) 1, 3 and 4 only
(b) 1 and 2 only
(c) 2, 3 and 4 only
(d) 1, 2, 3 and 4
Answer: (a) 1, 3 and 4 only
Explanation:
• Statement 1 is correct: CAR-T therapy genetically engineers T cells to recognize and destroy diseased cells.
• Statement 2 is incorrect: HIV primarily attacks CD4 T cells, not B cells.
• Statement 3 is correct: Modified CAR-T cells are multiplied in the laboratory before infusion.
• Statement 4 is correct: B cells provide humoral immunity, while T cells are responsible for cell-mediated immunity.
