Validation of immune complex dissociation methods for use with heartworm antigen tests
Abstract Background Antigen testing is routinely used to diagnose canine Dirofilaria immitis infections. Immune complex dissociation (ICD) methods, which were employed in the original heartworm antigen tests to release antigen that was bound by endogenous canine antibodies, were discontinued with im...
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doaj-cdb8f6a356a6459ca1f722bcd2fde92d2020-11-25T00:30:29ZengBMCParasites & Vectors1756-33052017-11-0110S211512110.1186/s13071-017-2442-8Validation of immune complex dissociation methods for use with heartworm antigen testsMelissa J. Beall0Andrea Arguello-Marin1Jan Drexel2Jiayou Liu3Ramaswamy Chandrashekar4A. Rick Alleman5IDEXX Laboratories, IncIDEXX Laboratories, IncIDEXX Laboratories, IncIDEXX Laboratories, IncIDEXX Laboratories, IncLighthouse Veterinary ConsultantsAbstract Background Antigen testing is routinely used to diagnose canine Dirofilaria immitis infections. Immune complex dissociation (ICD) methods, which were employed in the original heartworm antigen tests to release antigen that was bound by endogenous canine antibodies, were discontinued with improvements in assay reagents. The purpose of this study was to evaluate different ICD methods for detection of heartworm antigen by microtiter plate ELISA and assess the performance in samples from pet dogs. Methods The original PetChek® Heartworm Test (IDEXX Laboratories, Inc.) utilized pepsin at an acidic pH for ICD prior to antigen testing. Performance and characteristics of the pepsin ICD method were compared with those for heat treatment (with and without EDTA) and acid treatment. Results All four methods released complexed antigen in serum samples when tested using microtiter plate ELISA. Heat treatment required ≥600 μL of serum or plasma, whereas pepsin and acid methods needed only a 50-μL sample. Samples from 1115 dogs submitted to IDEXX Laboratories between 2014 and 2016 for investigation of discrepant heartworm results were evaluated with and without pepsin ICD using the PetChek Heartworm Test. Samples from 10% (n = 112) of the dogs were antigen positive with the ICD protocol only while 90% of the results remained unchanged. In a prospective study, antigen levels with and without ICD were evaluated for 12 dogs receiving pre-adulticide heartworm treatment with a macrocyclic lactone and doxycycline for 28 days. Serial samples revealed that three dogs had a reduction in detectable heartworm antigen within 4 weeks of initiating treatment. In these cases, heartworm antigen levels could be recovered with ICD. Conclusions Heartworm antigen testing with ICD can be a valuable diagnostic tool for patients with discrepant results that have had intermittent use of a preventive, or have been treated with a macrocyclic lactone and doxycycline. Heartworm therapies may reduce antigen production and favor immune complexing in some dogs, resulting in false-negative results. Therefore, it is important to confirm positive heartworm antigen test results before initiating therapy.http://link.springer.com/article/10.1186/s13071-017-2442-8Antigen testDirofilaria immitisHeartwormImmune complex dissociationSlow-kill |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Melissa J. Beall Andrea Arguello-Marin Jan Drexel Jiayou Liu Ramaswamy Chandrashekar A. Rick Alleman |
spellingShingle |
Melissa J. Beall Andrea Arguello-Marin Jan Drexel Jiayou Liu Ramaswamy Chandrashekar A. Rick Alleman Validation of immune complex dissociation methods for use with heartworm antigen tests Parasites & Vectors Antigen test Dirofilaria immitis Heartworm Immune complex dissociation Slow-kill |
author_facet |
Melissa J. Beall Andrea Arguello-Marin Jan Drexel Jiayou Liu Ramaswamy Chandrashekar A. Rick Alleman |
author_sort |
Melissa J. Beall |
title |
Validation of immune complex dissociation methods for use with heartworm antigen tests |
title_short |
Validation of immune complex dissociation methods for use with heartworm antigen tests |
title_full |
Validation of immune complex dissociation methods for use with heartworm antigen tests |
title_fullStr |
Validation of immune complex dissociation methods for use with heartworm antigen tests |
title_full_unstemmed |
Validation of immune complex dissociation methods for use with heartworm antigen tests |
title_sort |
validation of immune complex dissociation methods for use with heartworm antigen tests |
publisher |
BMC |
series |
Parasites & Vectors |
issn |
1756-3305 |
publishDate |
2017-11-01 |
description |
Abstract Background Antigen testing is routinely used to diagnose canine Dirofilaria immitis infections. Immune complex dissociation (ICD) methods, which were employed in the original heartworm antigen tests to release antigen that was bound by endogenous canine antibodies, were discontinued with improvements in assay reagents. The purpose of this study was to evaluate different ICD methods for detection of heartworm antigen by microtiter plate ELISA and assess the performance in samples from pet dogs. Methods The original PetChek® Heartworm Test (IDEXX Laboratories, Inc.) utilized pepsin at an acidic pH for ICD prior to antigen testing. Performance and characteristics of the pepsin ICD method were compared with those for heat treatment (with and without EDTA) and acid treatment. Results All four methods released complexed antigen in serum samples when tested using microtiter plate ELISA. Heat treatment required ≥600 μL of serum or plasma, whereas pepsin and acid methods needed only a 50-μL sample. Samples from 1115 dogs submitted to IDEXX Laboratories between 2014 and 2016 for investigation of discrepant heartworm results were evaluated with and without pepsin ICD using the PetChek Heartworm Test. Samples from 10% (n = 112) of the dogs were antigen positive with the ICD protocol only while 90% of the results remained unchanged. In a prospective study, antigen levels with and without ICD were evaluated for 12 dogs receiving pre-adulticide heartworm treatment with a macrocyclic lactone and doxycycline for 28 days. Serial samples revealed that three dogs had a reduction in detectable heartworm antigen within 4 weeks of initiating treatment. In these cases, heartworm antigen levels could be recovered with ICD. Conclusions Heartworm antigen testing with ICD can be a valuable diagnostic tool for patients with discrepant results that have had intermittent use of a preventive, or have been treated with a macrocyclic lactone and doxycycline. Heartworm therapies may reduce antigen production and favor immune complexing in some dogs, resulting in false-negative results. Therefore, it is important to confirm positive heartworm antigen test results before initiating therapy. |
topic |
Antigen test Dirofilaria immitis Heartworm Immune complex dissociation Slow-kill |
url |
http://link.springer.com/article/10.1186/s13071-017-2442-8 |
work_keys_str_mv |
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