3
HIV Causes a Breakdown of the Immune
Response 356
• Human immunodeficiency virus (HIV) is a retrovirus that
attacks helper T cells of the lymphatic system. The virus
incorporates its genetic information in the host's DNA and
forces the host cell to make new viruses. Ultimately, the host
cell dies and the virus spreads to other cells. In time, all the
helper T cells are destroyed and the infection proceeds to
acquired immunodeficiency syndrome (AIDS).
• As shown, AIDS patients suffer from numerous constitutional
symptoms, including chronic fatigue, weight loss, night
sweats, skin rashes, and various lesions of the mouth and
gums. They are susceptible to a host of opportunistic diseases
that would be fended off easily by a healthy lymphatic system.
• HIV is present in blood and body fluids. It is passed from
person to person through the exchange of body fluids (via
unprotected sexual intercourse, anal intercourse, oral sex,
and sharing of intravenous drug needles). It is not transmit-
ted by insect bites or casual contact.
• While there is no cure for HIV/AIDS, patients have respond-
ed to combinations of reverse transcriptase inhibitors and
protease inhibitors. While these drugs inhibit HIV replica-
HIV/AIDS • Figure 12.13a
Main symptoms of AIDS
Neurological
• Encephalitis
• Meningitis
Eyes
• Retinitis
Lungs
• Pneumocystis
pneumonia
• Tuberculosis
(multiple organs)
• Tumors
Skin
• Tumors
Gastrointestinal
• Esophagitis
• Chronic diarrhea
• Tumors
tion, help restore T cell counts, and improve general health,
an infected patient on this therapy can still transmit the
virus to another person. Even with treatment, the disease is
usually fatal.
Key Terms
• acquired immunodeficiency syndrome
(AIDS) 362
• active immunity 360
• adaptive immunity 350
• afferent lymphatic vessels 347
• allergen 360
• allergy 360
• anaphylactic shock 360
• antibody 348
• antibody-mediated immunity 354
• antigen 350
• antigen-presenting cell (APC) 356
• antimicrobial proteins 352
• autoimmune disease 361
• autoimmunity 361
• B cell 352
• B lymphocyte 354
• cell-mediated immunity 354
• clonal activation 356
• clonal selection 354
• complement proteins 352
• cytotoxic T cells 354
• efferent lymphatic vessels 347
• fever 353
• granulysins 357
• granzymes 357
• highly active antiretroviral therapy
(HAART) 362
• histamine 360
• human immunodeficiency virus
(HIV) 362
• immunity 348
• immunoglobulin 359
• immunological memory 359
• inflammation 352
• innate immunity 350
• interferons 352
• iron-binding proteins 352
• lymph 344
• lymph node 344
• lymphatic capillary 344
• lymphatic nodule 344
• lymphatic vessel 344
• lymphocyte 348
• major histocompatibility complex
(MHC) 356
• passive immunity 360
• pathogen 348
• phagocyte 352
• phagocytosis 352
• perforins 357
• primary lymphatic organs 344
• protease inhibitor 362
• red bone marrow 344
• reverse transcriptase inhibitor 362
• right lymphatic duct 344
• secondary lymphatic organs and
tissues 344
• spleen 344
• T cell 352
• T lymphocyte 354
• thoracic duct 344
• thymus 344
• vaccination 360
• vaccine 360
366 CHAPTER 12
The Lymphatic System and Immunity
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