Generation and characterization of D-dimer specific monoclonal antibodies for use in latex agglutination test

Immunoreactivity of canine, feline, and equine D-dimer with antibodies to human D-dimer

BACKGROUND

Commercially available D-dimer assays use antibodies against human D-dimer, with limited sensitivity and specificity data in companion animals.

OBJECTIVES

To evaluate the immunoreactivity of D-dimer in plasma of dogs, horses, and cats with commercially available antibodies to human D-dimer.

ANIMALS

Plasma samples were collected from healthy dogs and horses, and from surplus feline plasma submitted for diagnostic purposes.

METHODS

Descriptive research study. A cross-linked fibrin lysate was prepared from plasma samples, and SDS-PAGE and immunoblotting were performed with a variety of commercially available antibodies to human D-dimer.

RESULTS

The selected antibodies demonstrated variable reactivity with D-dimer of each species. The monoclonal antibody DD44 bound canine D-dimer with good specificity and sensitivity, but this antibody did not react with feline or equine D-dimer. The polyclonal antibody D2D bound putative D-dimer in dogs, cats, and horses with good specificity, and higher sensitivity compared to human D-dimer.

CONCLUSIONS AND CLINICAL IMPORTANCE

The variable performance of commercially available human D-dimer assays between species is, in part, because of inter-species variation in D-dimer immunoreactivity. The use of these assays should follow validation studies. Monoclonal antibody DD44 could be a focus for the development of a canine-specific assay.

Evaluation of the performance of a human D-dimer test in dogs with neoplasia

The goal of this study was to evaluate the suitability of a commercially available D-dimer assay as a diagnostic tool for testing dogs. This assay is an immunoturbidimetric diagnostic test, capable of determining the D-dimer levels in human plasma by using 2B9 monoclonal antibody. Plasma samples of clinically healthy (n = 20) and tumour-bearing (n = 50) dogs were measured. The tumours were grouped on the basis of histological type and aggressiveness, and then the measured D-dimer concentrations of these groups were compared to those of the control group. The differences were analysed statistically. For benign tumours, we did not find alterations in the D-dimer levels. However, in the case of malignant tumours (lymphoma, sarcoma, and carcinoma) and in the presence of metastases, significantly elevated D-dimer levels were measured. The assay proved to be suitable for measuring the D-dimer levels in plasma samples of dogs. The calculated reference range for dogs was confirmed to be between 0.06 and 0.69 µg/mL fibrinogen equivalent unit.