FITC-conjugated anti-bacteria primary antibodies combine high bacterial antigen specificity with fluorescein isothiocyanate (FITC) fluorescence, enabling direct visualization and quantification of pathogens using standard fluorescence microscopy, flow cytometry, and fluorescent immunoassays.
These ready-to-use reagents eliminate the need for secondary antibodies, reducing background signal and assay time while providing bright green fluorescence (excitation 488 nm, emission 525 nm).
FITC Conjugation Chemistry
FITC covalently binds to primary amines on lysine residues and N-termini via isothiocyanate chemistry, typically resulting in 2–4 fluorophores per IgG molecule. This conjugation strategy preserves more than 90% of antigen-binding affinity while ensuring a photostable fluorescent signal compatible with both fixed and live-cell applications.
- Molecular weight: 389 Da (minimal impact on antibody structure and function)
- Quantum yield: 0.92 (high fluorescence intensity)
- Stokes shift: 35 nm (efficient spectral separation)
- pH stability: Maintains fluorescence across pH 4.0–9.0
Major Applications
Direct Fluorescent Antibody (DFA) Assays: Rapid pathogen detection in clinical samples such as sputum, throat swabs, and cerebrospinal fluid (CSF):
- Legionella pneumophila: Detection from sputum samples
- Mycoplasma pneumoniae: Confirmation of atypical pneumonia
- Rabies virus: Brain tissue staining (reference diagnostic method)
Flow Cytometry Bacterial Detection:
- Enumeration of Staphylococcus aureus in blood cultures
- Escherichia coli serotyping in food and water analysis
- Assessment of antibiotic susceptibility via membrane integrity assays
Fluorescence Microscopy:
- Helicobacter pylori localization in gastric biopsy specimens
- Listeria monocytogenes invasion studies in cell culture models
- Visualization and structural analysis of bacterial biofilms