Chapter 25 Immunomodulators Flashcards
What is the primary goal of immunostimulant therapy in equine patients?
To enhance endogenous immunity in a non-antigen-specific manner.
When might immunostimulant therapy be used prophylactically in horses?
Prior to pathogen challenge or stressful situations like weaning or long-distance transport.
In what settings is immunostimulant therapy used concurrently with antimicrobial therapy?
To further enhance endogenous immune clearance mechanisms in combination with targeted pathogen treatment.
What are some immunologic mechanisms involved in innate immunity?
Rapid destruction of invading pathogens without memory or antigenic specificity, and activation of adaptive responses via antigen-presenting cells.
What is the role of pattern recognition receptors (PRRs) in innate immunity?
They recognize pathogen-associated molecular patterns (PAMPs) and initiate immune responses.
What are some examples of pattern recognition receptors (PRRs)?
Mannose receptor, CD14, peptidoglycan recognition protein (PGRP), scavenger receptors (SR), Toll-like receptors (TLRs), and nucleotide oligomerization domain/caspase recruitment domain (NOD/CARD).
What is the significance of Toll-like receptors (TLRs) in innate immunity?
They recognize microbial, viral, and fungal conserved structures and play a crucial role in immune response activation.
What is the function of Toll-like receptor-9 (TLR-9)?
Recognizes unmethylated CpG-containing DNA motifs found in intracellular bacteria and viruses.
What is the role of Toll-like receptor-7 (TLR-7)?
Recognizes small synthetic immune modifiers and has applications in clinical use against viral infections and cancers.
What are some commercially available immunostimulants for use in horses?
Inactivated Parapoxvirus ovis (Zylexis), Propionibacterium acnes extract (EqStim), Mycobacterial cell wall extract (Equimune IV), Interferon-alpha (Intron A), Imiquimod (Aldara), Granulocyte-colony stimulating factor (Neupogen), and Levamisole phosphate.
What is Inactivated Parapoxvirus ovis (iPPVO) used for in horses?
To enhance immunity before a stressful event or during disease, particularly for respiratory disorders caused by equine herpesvirus-1 (EHV-1) and EHV-4.
What are the immunologic benefits of Inactivated Parapoxvirus ovis (iPPVO)?
Activation of antigen-presenting cells (APCs) and up-regulation of inflammatory cytokines IL-6, IL-8, TNF-alpha, and Th1 response-inducing cytokines IL-12 and IL-18.
What is the role of Propionibacterium acnes extract (EqStim) in equine medicine?
Treatment of chronic, exudative respiratory disease and prophylactic administration prior to stressful events that may impair pulmonary defense mechanisms.
What are the effects of Propionibacterium acnes on the immune system?
Stimulation of macrophage function, natural killer cytotoxicity, cytokine production (IL-1, IFN-gamma), and enhanced immune activation.
What is Mycobacterial cell wall extract (MCWE) used for in horses?
Treatment of infectious respiratory disease and post-breeding endometritis.
What is the mechanism of action of Mycobacterial cell wall extract (MCWE)?
Potent stimulation of nonspecific immunity, inducing cytokine production and enhancing immune responses.
What is the role of Interferon-alpha (IFN-alpha) in equine immunomodulation?
Demonstrates antiviral, immunomodulatory, and antiproliferative properties, and enhances natural killer cell cytotoxicity and macrophage activation.
What are the benefits of oral administration of IFN-alpha in horses?
Reduces inflammation in the lower respiratory tract, lowers total cell counts in bronchoalveolar lavage fluid (BALF), and converts the differential cell count to a non-inflammatory cytologic profile.
