Table 4.

Summary of M. paratuberculosis serology studies in the last decade

TestaAnimal speciesType of immune responsebInfection statuscSummary of resultsReference
Absorbed ELISACattleHumoralNAd Absorption of sera with M. phlei significantly increased the sensitivity of the test by reducing false-positives results 81
AGID, CF, LAM-ELISACattleHumoralNALAM-ELISA was more accurate in predicting the infection status of an animal than either the CF or AGID test 199
Absorbed ELISACattleHumoralNot infected; clinical, shedding; subclinical, shedding; subclinical, low sheddingA significant increase in ELISA response was noted for animals shedding M. paratuberculosis; absorption of sera with M. phleiincreased the ELISA sensitivity for all groups of animals 16
Absorbed ELISA nonabsorbed ELISACattleHumoralClinical, shedding; subclinical, shedding; subclinical, low sheddingBoth ELISAs were significantly more sensitive for heavy shedders; absorption of sera with M. phlei decreased sensitivity and increased specificity for both groups of animals 17
IFN-γ ELISA, IFN-γ bioassay, absorbed ELISACattleHumoral and  cellularClinical, shedding; subclinical, shedding; subclinical, low sheddingIFN-γ ELISA was better at detecting animals in the subclinical stage of disease 23
AGID, CF, IDEXX ELISA, CSL ELISACattleHumoralShedders; nonsheddersOverall, ELISA test was more sensitive than either the CF or AGID test; all tests performed better at detecting antibodies from animals shedding bacteria 270
Absorbed ELISA, nonabsorbed ELISACattleHumoralClinical, shedding; subclinical, shedding; subclinical, low sheddingBoth ELISAs were significantly more sensitive for heavy shedders; absorption of sera with M. phlei decreased sensitivity and increased specificity for both groups of animals 18
AGIDSheepHumoralDiffuse histologic lesions; discrete histologic lesionsSheep with diffuse lesions tended to have higher AGID scores than did sheep with discrete lesions 262
IDEXX ELISAGoatsHumoralInfected animals; noninfected animalsThe ELISA was comparable in sensitivity (54%) and specificity (99%) to similar tests done in cattle 30
AGID, CF, CSL ELISA, nonabsorbed ELISASheepHumoralGrossly detectable lesions; histologically detectable lesions; no histological lesionsThere were no differences among the tests in their ability to identify clinical or subclinical stages of disease (grossly detectable vs histologically detectable lesions); all tests performed better for animals in the later stages of disease 153
PPA-3 AGID, IFN-γ test SheepHumoral and  cellularDiffuse histologic lesions; discrete histologic lesionsThe IFN-γ test detected infected animals sooner than did the AGID test; no positive animals were detected until 120 days postinfection; diffuse lesions were correlated with positive AGID and negative IFN-γ results 234
LAM-ELISACattleHumoralInfected animals; noninfected animalsMilk and serum samples from the same animals had comparable LAM-ELISA results 288
AGID, IDEXX ELISACattleHumoralClinical symptoms; no clinical symptomsThe ELISA was more sensitive than the AGID test; the ELISA did not detect some animals that were positive by the AGID test 84
IDEXX ELISASheepHumoralClinical; subclinical; not infectedELISA was more sensitive in detecting clinically infected than subclinically infected sheep 96
IDEXX ELISACattleHumoralClinical, shedding; subclinical, shedding; subclinical, low shedding; not infectedThe sensitivity of the test was highest for clinical cases and lowest for subclinically infected animals shedding small numbers of bacteria 289
AGID, absorbed ELISASheepHumoralDiffuse histologic lesions; discrete histologic lesionsBoth ELISA and the AGID test were sensitive for detecting animals with diffuse lesions; the sensitivity of both tests was significantly lower for animals with discrete lesions 57
AGIDSheepHumoralInfected animals; noninfected animalsThe commercially available AGID test approved for use in cattle was able to identify 25 of 27 infected sheep, indicating that it is useful for diagnosing paratuberculosis in sheep 97
LAM-ELISACattleHumoralInfected animals; noninfected animalsThe LAM preparation used as antigens for the ELISA was standardized; the standardized test had a positive predictive value of 74% 160
PPA-3 AGID, PPA-3 ELISASheepHumoralDiffuse histologic lesions; discrete histologic lesionsThe serology test results corresponded to the type of histological lesion; all animals that were positive by AGID serology had diffuse lesions; all animals with acid-fast bacilli in the lesions were positive by the AGID test and ELISA 235
PPA-3 ELISA, LAM-ELISA, CSL ELISACattleHumoralNAInhibition ELISA studies demonstrated that PPA-3 and LAM antigens cross-react but that CSL and LAM antigens do not 284
IDEXX ELISA, LAM-ELISA, Absorbed LAM-ELISA, HSP-ELISACattleHumoralNAPreabsorption of the LAM-ELISA with M. phlei decreased the number of positive results; not all animals were classified as positive by the different tests; the HSP-ELISA was the least sensitive of all the tests 85
CSL IFN-γ ELISACattleCellularInfected animals; noninfected animals; vaccinated animals2 of 10 infected calves had positive IFN-γ results; 3 of 9 vaccinated calves had positive IFN-γ results; all four noninfected calves were positive by IFN-γ ELISA 197
CSL IFN-γ ELISA, DTHSheepCellularDiffuse lesions, shedders; borderline discrete lesions, low shedders; discrete lesions, low sheddersSheep with discrete lesions were positive by IFN-γ EIA and DTH; sheep with diffuse lesions and shedding large numbers of bacteria were negative 236
CF, DTH, IDEXX ELISAGoatsHumoral and  cellularExperimentally infected animalsInfection could not be confirmed histologically until at least 17 wk postinfection, and all serology tests were unable to detect infection until 37 wk postinfection263
  • a Absorbed ELISA, test serum absorbed with M. phlei antigens to remove cross-reacting antibodies. AGID, agar gel immunodiffusion test; CF, complement fixation test; LAM-ELISA, lipoarabinomannin antigen ELISA; nonabsorbed ELISA, test serum is not preabsorbed with other mycobacterial antigens; IFN-γ-ELISA, gamma interferon ELISA; PPA-3 ELISA, protoplasmic peptide antigen ELISA; CSL ELISA, commercially available ELISA kit (PARACHEKT) from CSL Ltd., Parkville, Australia; IDEXX ELISA, commercially available ELISA test kit from IDEXX Laboratories Inc., Westbrook, Me; absorbed LAM ELISA, absorbed ELISA using lipoarabinomannin extracts as capture antigens; HSP-ELISA, ELISA using the 65-kDa heat shock protein as a capture antigen; CSL IFN-γ ELISA, commercially available IFN-γ test kit (BOVIGAM) from CSL Ltd.; DTH, delayed-type hypersensitivity reaction.

  • b Type of immune response detected by the test.

  • c Description of infection status of study animals, as described in the reference.

  • d NA, not applicable.