Genetic Engineering and Immunology

Posted on Dec 4, 2024 in Biology

Genetic Engineering

Genetic engineering is the manipulation of DNA to change the genome of a living being. Changes include:

  • Introducing new genes into a genome
  • Deleting existing genes from a genome
  • Modifying the information contained within a gene
  • Changing gene expression
  • Cloning beings, organs, or tissues

Cloning

Cloning is making a genetically identical copy (may be a gene, cell, or organism).

  • Molecular Cloning: Isolates the DNA fragment containing the genes of interest, binds it to a DNA fragment in a cloning vector, re-enters the bacterial, allows bacterial multiplication, and then extracts the desired gene.
  • Cell Cloning: Produces many cells from one.
  • Organism Cloning: Creates a new agency with the same genetic information as an existing organism or cell.
  • Artificial Cloning: Based on nuclear transfer (one cell donates genetic material and another accepts it).

Stem Cells

Stem cells are unspecialized cells that give rise to other cell types. They are responsible for growth and tissue repair. There are three types:

  • Embryonic:
    • Totipotent: Can lead to a full organism.
    • Pluripotent: May produce any tissue.
  • Adult:
    • Multipotent: Only create specific cell types within a tissue.
Transgenic Organisms

Transgenic organisms carry artificially introduced genes in their genome. This has implications for medicine, including the study of human diseases and human protein production.

Transgenic Food

Transgenic food refers to food that has been genetically modified.

Immunology

The immune system’s main function is to distinguish self from foreign entities.

Natural Defense Mechanisms

Non-Specific Defense Mechanisms:

  • Primary Barriers: Skin (squamous, sweat, etc.) and natural openings (saliva, mucus, tears).
  • Secondary Barriers (Active Defense): Act via phagocytosis, performed by white blood cells (leukocytes): monocytes (macrophages) and neutrophils. The inflammatory response produces leukocytes that travel through the blood and activate molecules when tissue lesions are caused by invaders. When a lesion occurs in a tissue, it triggers diapedesis, increasing blood flow to the affected area and producing inflammation. White blood cells then clean the affected area.

Specific Defense Mechanisms

  • Antigen: A substance that triggers the immune system and causes antibody formation (typically glycoprotein, protein, or lipid).
  • Determinant Groups: Groups of the antigen molecule responsible for specific antibody formation.
  • Hapten: Does not cause antibody production unless combined with another molecule.
  • Lymphoid Tissues and Organs:
    • Primary: Form and mature lymphocytes (bone marrow and thymus).
    • Secondary: Where lymphocytes perform their action (spleen, tonsils, lymph nodes).
  • Cells:
    • T cells: Formed in bone marrow and mature in the thymus. Responsible for cellular response. Types: cytotoxic (attack foreign cells), helper (stimulate B lymphocytes to produce interleukins), and suppressor (inhibit B lymphocytes).
    • B cells: Differentiate into plasma cells that make antibodies. Formed and mature in bone marrow. Responsible for humoral response.
    • Killer cells: Attack foreign particles, distinguishing between healthy and diseased cells.
  • Antibodies: Proteins of the γ-globulin type, formed by four polypeptide chains.
  • Immune Response: The organism recognizes and removes a specific agent. It has memory: the organism remembers if it has encountered the same agent before. Two types:
    • Primary Immune Response: Occurs at first contact with an antigen. Slow response.
    • Secondary Immune Response: Occurs at second and subsequent contacts with the same antigen. Fast response.
  • Complement System: Enhances the action of antibodies. Activated by the presence of antigens via classical or alternative pathways.

Types of Immunity

  • Natural: Animals develop natural immunity when exposed to a bacterial invasion. The immune system produces antibodies against these microorganisms. Active process.
  • Passive Natural: Mammals acquire natural immunity through antibodies received from the mother via the placenta. Passive process.
  • Artificial Active: Introduction of dead or weakened antigens through vaccines. Preventive.
  • Artificial Passive: Introduction of antibodies against the disease-causing microorganisms through serums. Curative.

Immune System Disorders

  • Allergies: Exaggerated immune system response to harmless substances (allergens). Allergic reactions can affect the respiratory and digestive systems. Two phases: sensitization and second contact.
  • Autoimmune Diseases: Abnormal functioning of the immune system, reacting against body cells and damaging them. Can affect specific tissues or the whole body. May be caused by some microorganisms or medications.

Antibiotics

Antibiotics are agents produced by other microorganisms, such as fungi, that alter metabolic pathways. They are effective against bacteria, but not viruses. An example is penicillin.