hg4_lect28免疫系統(tǒng)的遺傳學(xué)-資料下載頁
2024-10-04 22:39本頁面
【正文】 ine deaminase) target disease for gene therapy AIDS Acquired immunodeficiency syndrome collection of disorders that develop as a result of infection with HIV HIV , human immunodeficiency virus (retrovirus). virus infects macrophages and T4 helper cell Problem T cell activation also activates viral replication with time, the helper T cells are killed off eventually loose ability to activate the antibodymediated immune response result increased susceptibility to infection and certain forms of cancer early death Structure of HIV HIV is an RNA virus (a retrovirus). The RNA molecule encodes a reverse transcriptase enzyme which synthesizes a DNA copy of the RNA virus. The virus is enclosed within a capsid within a coating of envelope protein studded with glycoproteins that can bind cell surface molecules on the host cell. HIV envelope proteins gp41 and gp120 bind to CD4 and CCR5 receptors on the helper T cell. Final note on AIDS: its not that the immune system can’t fight the HIV infection, it just can’t keep up early HIV infections produce 2 billion new B and T cell per day virus does two things produces millions to billions of new virus per day it mutates very rapidly antibodies useful today – no effect tomorrow Treatment of HIV infection ? Drug therapies have cut the mortality rate from AIDS in half since 1996. ? Two reverse transcriptase inhibitors and a protease inhibitor are monly used. ? Reverse transcriptase inhibitors block conversion of the viral RNA into DNA. ? The protease inhibitor limits the processing of several viral proteins required for new particle formation. Resistance to AIDS? Are some individuals less susceptible to AIDS than others? People at high risk for HIV infections (individuals with multiple partners or hemophilia) who are not infected more often have a CCR5 receptor gene with a 32base deletion. This deletion truncates the protein and prevents localization to the cell surface. Long term nonprogressors are infected but healthy. Correlated with heterozygous carriers of CCR5 deletion. Correlated with milder inflammation response. Disorders of the Immune system Allergies overreactions of the immune system weak antigens are called allergens house dust, pollen, cat dander food, medicines up 10% of us have at least one allergy Problem relates to Immune response memory Mast cell release histamine local inflammatory response if histamine enter blood stream in high amounts full body response anaphylaxis treat with antihistamines epinephrine Asthma a chronic disease involving contraction of the respiratory airways, inflammation and mucus production in the lungs. Breathing bees difficult during an asthma attack. Some asthma attacks are triggered by allergic reactions. Allergic response Humoral and cellular arms respond. IgE class antibodies are made and bind mast cells. Mast cells release allergy mediators like histamine and heparin that cause inflammation, runny eyes and nose, rashes and asthma. Allergens activate a class of helper T cells which release cytokines. Severe allergic reaction throughout the body is called anaphylatic shock and can be lifethreatening.
環(huán)評(píng)公示相關(guān)推薦
鄂ICP備17016276號(hào)-1