Chapter 40 Flashcards
Acquired immunodeficiency syndrome (AIDS)
Infection caused by the human immunodeficiency virus (HIV), which weakens the host’s immune system, giving rise to opportunistic infections
Antibodies
Immunoglobin molecules that have an antigen-specific amino acid sequence and are produced by the humoral immune system (antibodies produced from B lymphocytes) in response to exposure to a specific antigen, the purpose of which is to attack and destroy molecules of this antigen
Antigen
A substance, usually a protein, that is foreign to a host and causes the formation of an antibody that reacts specifically with that antibody
Examples: bacterial exotoxins, viruses, allergens
An allergen (dust, pollen, mold) is a specific type of antigen that causes allergic reactions
Antiretroviral drugs
A specific term for antiviral drugs that work against retroviruses such as HIV
Antiviral drugs
A general term for drugs that destroy viruses, either directly or indirectly by suppressing their replication
Cell-mediated immunity
One of two major parts of the immune system. It consists of nonspecific immune responses mediated primarily by T lymphocytes (T cells) and other immune system cells (e.g., monocytes, macrophages, neutrophils) but not by antibody-producing cells (B lymphocytes)
Deoxyribonucleic acid (DNA)
A nucleic acid composed of nucleotide units that contain molecules of the sugar deoxyribose, phosphate groups, and purine and pyrimidine bases. DNA molecules transmit genetic information and are found primarily in the nuclei of cells
Fusion
The process by which viruses attach themselves to, or fuse with, the cell membrane of host cells, in preparation for infecting the cell for purposes of viral replication
Genome
The complete set of genetic material of any organism; it may consist of multiple chromosomes (groups of DNA or RNA molecules) in higher organisms; a single chromosome, as in bacteria; or one or two DNA or RNA molecules, as in viruses
Herpesviruses
Several different types of viruses belonging to the family Herpesviridae that cause various forms of herpes infection
Host
Any organism that is infected with a microorganism, such as bacteria or viruses
Human Immunodeficiency Virus (HIV)
The retrovirus that causes AIDS
Humoral Immunity
One of two major parts of the immune system. It consists of specific immune responses in the form of antigen-specific antibodies produced from B lymphocytes
Immunoglobins
Synonymous with immune globulins. GLycoproteins produced and used by the humoral immune system to attack and kill any substance (antigen) that is foreign to the body. An immunoglobulin with an antigen-specific amino acid sequence is called an antibody and is able to recognize and inactivate molecules of a specific antigen
Influenza viruses
The viruses that cause influenza, an acute viral infection of the respiratory tract. There are three types of influenza virus: A, B, and C. Currently, medications are available only to treat types A and B
Nucleic Acid
A general term referring to DNA and RNA
These complex biomolecules contain the genetic material of all living organisms, which is passed to future generation during reproduction
Nucleoside
A structural component of nucleic acid molecules (DNA or RNA) that consists of a purine or pyrimidine base attached to a sugar molecule
Nucleotide
A nucleoside that is attached to a phosphate unit, which makes up the side chain “backbone” of a DNA or an RNA molecule
Opportunistic infections
Infections caused by any type of microorganism that occur in an immunocompromised host but normally would not occur in an immunocompetent host
Protease
An enzyme that breaks down the amino acid structure of protein molecules by chemically cleaving the peptide bonds that link together the individual amino acids
Replication
Any process of duplication or reproduction, such as that involved in the duplication of nucleic acid molecules (DNA or RNA) during the reproduction processes of all living organisms. This is also the term used most often to describe the entire process of viral reproduction, which occurs only inside the cells of an infected organism
Retroviruses
Viruses belonging to the family Retroviridae. These viruses contain RNA (as opposed to DNA) as their genome and replicate using the enzyme reverse transcriptase. Currently the most clinically significant retrovirus is HIV
Reverse Transcriptase
An RNA-directed DNA polymerase enzyme. It promotes the synthesis of a DNA molecule from an RNA molecule, which is the reverse of the usual process. HIV replicates in this manner
Ribonucleic Acid (RNA)
A nucleic acid composed of nucleotide units that contain molecules of the sugar ribose, phosphate groups, and purine and pyrimidine bases. RNA molecules transmit genetic information and are found in both the nuclei and cytoplasm of cells.
Virion
A mature virus particle
Viruses
The smallest known class of microorganisms; viruses can only replicate inside host cells
acyclovir (Zovirax) Mechanism of Action
Work by blocking the activity of a polymerase enzyme that normally stimulates the synthesis of new viral genomes
ganciclovir (Cytovene) Mechanism of Action
Work by blocking the activity of a polymerase enzyme that normally stimulates the synthesis of new viral genomes
indinavir (Crixivan) Mechanism of Action
Work by inhibiting the protease retroviral enzyme, which promotes the breakup of chains of protein molecules at designated points, which is necessary for viral replication
nevirapine (Viramune) Mechanism of Action
Work by blocking activity of the enzyme of reverse transcriptase, which promotes the synthesis of new viral DNA molecules from the RNA genome
ziovudine (Retrovir) Mechanism of Action
Work by blocking activity of the enzyme of reverse transcriptase, which promotes the synthesis of new viral DNA molecules from the RNA genome
