INTRODUCTION.

To protect mucosal surface against pathogens, numerous IgA secreting B cells are located in the intestinal lamina propria (LP).

The mammalian B cells are divided in based on their phenotypes, micro-anatomical localization and funtions.

B1 cells contribute to reinforcement of the gut barrier by producing poly-specific IgA and therefore funtion as a first layer of immune defense at the gut mucosa.

Some molecules as retinoic acid (RA) cause IgA isotype switching in mice. Recently was demostrated that lactoferrin (LF) causes IgA isotype switching in spleen B cells.

INTRODUCTION.

Product of the Vitamin A. Involved in the production of intestinal mucus. Take part in the mechanism of inflammatory reaction. IgA switching isotype. Control the T cell diferentiation.

Retinoic Acid (RA)

INTRODUCTION.

Monomeric glycoprotein (80 kDa). Abundant in mucosal surfaces and milk,

tears, bronchial and intestinal fluid, granules of neutrophils.

Antimicrobial propierties. Immunomodulator of innate and

adaptative immunity. Proliferative activity.

Lactoferrin (LF)

INVESTIGATE THE EFFECT OF LF + RA ON IgA PRODUCTION BY PERITONEAL B CELLS SUBSETS.

Material and Methods

Animals

C57BL/6

12-32 weeks

Retonoic acidLPS (Escherichia coli O111: B4)Bovine lactoferrinTGF-β1

• Reagents

• B cell preparations and cell culture

3 times /5 ml PBS

Macrophages depleted by

incubation for 3h

CD43+ (B1 cells) CD43- (B2 cells)500,000 cells/well (48 well

culture plates)

200,000 cells/well (96 well culture plates)

Material and Methods

• Isotype-specific ELISA

415 nm

• Flow cytometric analysis

Anti CD43-biotinAnti IgA-FITCAnti CD23-biotinAnti IgM-PEAnti CD45R/B220-biotinAnti CCR9-PEAnti LPAM1

Figure 1. Effect of LF, RA, and TGF- β1 on Ig secretion by mouse peritoneal B cells.

Figure 2. Effect of LF, RA, and TGF- β1 on Ig secretion by mouse peritoneal B1 and B2 cells.

Figure 3. Combined effect of LF and RA on Ig secretion by mouse peritoneal B1 and B2 cells.

Figure 4. Measurement of membrane IgA on freshly isolated peritoneal B1 and B2 cells.

Figure 5. Effect of LF and RA on gut homing molecule expressed by peritoneal B1 and B2 cells.