# COMPARATIVE AND DEVELOPMENTAL IMMUNOBIOLOGY

> **NIH NIH R37** · UNIVERSITY OF ROCHESTER · 1994 · $241,676

## Abstract

Recent studies have revealed that although the frog, Xenopus,
expresses class II molecules throughout larval and adult life,
tadpoles of this species do not express detectable class I antigens
until they reach metamorphic climax.  Hence, the larval frog
provides a unique "model of nature" (somewhat akin to humans
with the "bare lymphocyte" syndrome) with which to examine the
biological roles of class I and class II antigens and class I- and
class II-reactive T cells from an immunologic, ontogenetic, and
phylogenetic perspective.  The major goal of this proposal is to
better understand the importance, in Xenopus, of class I antigen
expression and anti-class I-reactive and class II-reactive T cells
on:  1) lymphocyte-target cell interactions, 2) the establishment
of self-tolerance and allotolerance, and 3) the ontogeny of the T
cell repertoire.  More specifically, I will use in vitro proliferative
and cytotoxic assays, skin grafting between larvae and adults,
embryonically created thymus/hematopoietic chimeras, and
molecular biological techniques to address the following
questions:

1.  During adult life, do class I and class II gene products serve as
target and restriction molecules of cytotoxic T cells?

2.  In the absence of class I expression, do tadpoles have class I-
restricted and anti-alloclass I-reactive cytotoxic T cells?

3.  Do class II molecules serve as restriction elements for both
helper and cytotoxic T cells of tadpoles?

4.  Is there a relationship between the lack of class I expression
and the ease with which tadpoles become tolerant of adult skin
allografts (i.e., do class II disparities favor tolerance induction)?

5.  If expression of class I molecules can be induced precociously
in tadpoles, does this accelerate maturation of anti-class I-
reactive T cells and facilitate development of autoimmunity?

6.  Does the thymus play a critical role in the acquisition of the T
cell repertoire, and when during ontogeny does it play this role?

7.  What rearrangements of T cell receptor genes occur during
ontogeny?

## Key facts

- **NIH application ID:** 2196296
- **Project number:** 5R37HD007901-27
- **Recipient organization:** UNIVERSITY OF ROCHESTER
- **SAM.gov UEI:** F27KDXZMF9Y8
- **Principal Investigator:** Nicholas Cohen
- **Activity code:** R37 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $241,676
- **Award type:** 5
- **Project period:** 1978-09-01 → 1998-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2196296

## Citation

> US National Institutes of Health, RePORTER application 2196296, COMPARATIVE AND DEVELOPMENTAL IMMUNOBIOLOGY (5R37HD007901-27). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2196296. Licensed CC0.

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