Anti Gut Bacteria Antibodies

The human gut contains a wide variety of microorganisms, including bacteria, which form diverse microbiotas that are well adapted to their environment. These microbiota, along with their metabolic products, have been linked to various diseases such as cancer, diabetes, obesity, allergies, and neuropsychiatric disorders, and are drawing increasing attention for their role in human health.
Gut bacteria such as Phocaeicola vulgatus, Faecalibacterium duncaniae, and Segatella copri. are commonly found in the Japanese population. By analyzing their relative abundance and identifying the enterotype of the gut microbiota, researchers can better understand an individual's intestinal environment. Although next-generation sequencing (NGS) is the primary method for analyzing gut bacteria, it continues to be both labor-intensive and costly.
As part of their effort to establish a rapid, cost-effective, and straightforward method for detecting gut bacteria, the research group led by Dr. Jun Kunisawa and Dr. Ken Yoshii at the National Institutes of Biomedical Innovation, Health and Nutrition has developed monoclonal antibodies that recognize the gut bacterial species specified above¹⁾. Using a non-targeted approach involving direct immunization of mice with individual bacterial strains, they successfully generated antibodies capable of recognizing these bacterial species.

Fujifilm Wako has a lineup of antibodies against the following three types of gut bacteria.

Name	Phocaeicola vulgatus			Faecalibacterium duncaniae			Segatella copri
Overview	Formerly known as Bacteroides vulgatus. This bacterium supports metabolic and immune functions. While generally considered a commensal organism, it can exhibit pathogenicity under certain conditions. Ongoing research on this genus aims at promoting health and preventing disease by modulating the gut microbiota.			Formerly known as Faecalibacterium prausnitzii. This anaerobic bacterium resides in the intestines of humans and animals. It is known to produce short-chain fatty acids and has been implicated in inflammatory bowel diseases such as ulcerative colitis and Crohn's disease.			Formerly known as Prevotella copri. This Gram-negative bacterium is found in various parts of the human body and has been linked to conditions such as periodontitis, inflammatory bowel disease, and bacterial vaginosis.
Product No.	013-28931	010-28941	017-28951	012-28901	019-28911	016-28921	014-28961	011-28971
Clone No.	PV-L2B7-117K1	PV-L1A6-117K2	PV-S10F7-14K1	FD-S2D3-18K1	FD-L4F6-18K2	FD-L5B6-33K2	SC-S10C3-49K1	SC-L10B5-35K1
Subclass	IgG2b	IgG2b	IgG3	IgG2b	IgG2b	IgG2b	IgG2a	IgG2a
Host	Mouse
Formulation	1 x D-PBS, 0.05% Sodium azide
Application	ELISA (Direct/Sandwich*), Flow cytometry, Immunoprecipitation, Western blotting

Quantification of Individual Gut Bacterial Species by Sandwich ELISA and Comparison with 16S rRNA Gene-Based NGS

Bacterial counts in three human fecal samples were measured using sandwich ELISA with combinations of anti-gut bacterial antibodies. Relative abundances obtained by sandwich ELISA were compared with those obtained from 16S rRNA gene amplicon sequencing via NGS¹⁾.

Combination of antibodies in ELISA

(1) P. vulgatus
Capture Antibody: PV-L1A6-117K2
Detection Antibody: PV-L2B7-117K1

(2) F. duncaniae
Capture Antibody: FD-S2D3-18K1
Detection Antibody: FD-L4F6-18K2

(3) S. copri
Capture Antibody: SC-S10C3-49K1
Detection Antibody: SC-S10C3-49K1

Quantification of Gut Bacterial Counts by Sandwich ELISA

• Phocaeicola vulgatus
• Faecalibacterium duncaniae
• Segatella copri

Comparison with 16S rRNA Gene-Based NGS

• Phocaeicola vulgatus
• Faecalibacterium duncaniae
• Segatella copri

ELISA

100 μL of a bacterial suspension was added to a 96-well microplate to coat the wells. The suspension was prepared either by diluting freeze-dried, heat-inactivated bacteria in PBS or by suspending them in B-PER solution followed by lysis with glass beads. After blocking and washing the antigen-coated plate, culture supernatants from individual hybridoma clones were added and incubated for 2 hours. Antibodies against gut bacteria bound to the antigens were detected using HRP-conjugated goat anti-mouse IgG¹⁾.

• P. vulgatus
• F. duncaniae
• S. copri
• B. pseudocatenulatum
• B. longum
• B. wexlerae
• A. muciniphila

Flow Cytometry

After fixation with Farmer’s fixative (ethanol:acetic acid = 7:3), the bacteria were centrifuged at 13,040 x g for 2 minutes at 4 °C. Next, 100 μL of the bacterial suspension was mixed with 1 μg of anti-gut bacterial antibody in PBS-T containing 1% BSA and incubated on ice for 1 hour. After washing, FITC-conjugated anti-mouse IgG was added, and the sample was incubated for 30 minutes on ice in the dark. The stained bacteria were then washed and analyzed by flow cytometry¹⁾.

Anti-P. vulgatus

Anti-F. duncaniae

Anti-S. copri

Data were compiled from reference 1) with permission from the author.

Western Blotting

Gut bacterial strains were collected by centrifugation at 10,000 x g for 5 minutes. Two micrograms of protein were separated by SDS-PAGE, transferred to a PVDF membrane, and blocked. Immunodetection was performed using 25–50 ng/mL of anti-gut bacterial antibody and HRP-conjugated mouse IgG¹⁾.

The samples used are gut bacteria extracts, as shown below.

P. vulgatus

: Phocaeicola vulgatus JCM5826

F. duncaniae

: Faecalibacterium duncaniae JCM31915

S. copri

: Segatella copri JCM13464

Data were compiled from reference 1) with permission from the author.

1. Yoshii, K. et al.: Sci. Rep., 15(1), 1(2025).
   Establishment of enterotype-specific antibodies for various diagnostic systems