DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY Printed in the United States
IMMUNOLOGY
Vol. l , pp. 395-396, 1977 Pergamon Press, Inc.
COURSES
Grace L. Rosenquist Dept. of Animal Physiology, University of California Davis, California 95616
When I had the opportunity to offer a course in Comparative Immunology, I wrote or telephoned some of my fellow immunologists with an interest in phylogeny to ask about the courses they had taught in the field. Much to my surprise, I was unable to find one person who had taught a similar course, although many admitted they would like to have the opportunity to do so. Now that the course is near completion, I have found that the comparative approach is more logical and presumably has left the students with a better and more lasting comprehension of the vertebrate immune system. I am writing in support of this approach, even when only one immunology course is offered at the university level. The students, some of whom had participated in conventional immunology courses, gained a new understanding of immune systems by reading and evaluating the literature in Comparative Immunology. I would like to list some of the comments which I have received from them. i. The study of the invertebrate "immune" system with the limited goal of finding similarities to the mammalian immune system has its disadvantages. It biases the student so that it is difficult to gain insights which may eventually lead to a new understanding of the mammalian immune system and how it was derived phylogenetically. 2. The evaluation of data from early recognition systems such as those seen in mating types in protozoa or sexual reproduction in colonial tunicates leads to the conclusion that these primitive systems were involved in the improvement or the heterozygosity of the species. These systems recall the recent data of Boyse and his associates which suggest that mating preferences of mice may be controlled by the major histocompatibility complex (MHC). It seems logical to assume that the MHC did not evolve to function in transplant rejection, which is a concept accepted by too many students. 3. T cell diversification is a complicated subject to students and veteran immunologists alike, but the observation that T cell function has its phylogenetic origin at least as early as the annelld provides the rationale for such diversity in the T cell system. 4. The complement system, which to many students is a long list of proteins interacting in cascade to lyse red blood cells, gained new importance when described in invertebrates. The fact that complement activity has been described in the echinoderm suggests that complement genes may have evolved before immunoglobulln genes. 395
396
IMMUNOLOGY COURSES
VoI.I,No.4
5. Therefore, it is apparent that the origins of the immune system must not be in lower vertebrates where classical immunoglobulin first appears, but in the invertebrates where elaborate recognition systems exist, although binding proteins homologous to immunoglobulines have not been found. The fact that ~mmunoglobulins and receptors throughout phylogeny are glycoproteins is a concept that is not generally stressed to students. As the course continued the idea of a membrane bound receptor evolving into a secreted immunoglobulin was accepted as logical development. I hope that my experience with this course will help those comparative and other immunologists who are apprehensive about teaching their immunology classes from an evolutionary viewpoint. It may not only be more exciting for them, but also more profitable for the students in the class.
IMMUNOLOGY
Vol. l , pp. 395-396, 1977 Pergamon Press, Inc.
COURSES
Grace L. Rosenquist Dept. of Animal Physiology, University of California Davis, California 95616
When I had the opportunity to offer a course in Comparative Immunology, I wrote or telephoned some of my fellow immunologists with an interest in phylogeny to ask about the courses they had taught in the field. Much to my surprise, I was unable to find one person who had taught a similar course, although many admitted they would like to have the opportunity to do so. Now that the course is near completion, I have found that the comparative approach is more logical and presumably has left the students with a better and more lasting comprehension of the vertebrate immune system. I am writing in support of this approach, even when only one immunology course is offered at the university level. The students, some of whom had participated in conventional immunology courses, gained a new understanding of immune systems by reading and evaluating the literature in Comparative Immunology. I would like to list some of the comments which I have received from them. i. The study of the invertebrate "immune" system with the limited goal of finding similarities to the mammalian immune system has its disadvantages. It biases the student so that it is difficult to gain insights which may eventually lead to a new understanding of the mammalian immune system and how it was derived phylogenetically. 2. The evaluation of data from early recognition systems such as those seen in mating types in protozoa or sexual reproduction in colonial tunicates leads to the conclusion that these primitive systems were involved in the improvement or the heterozygosity of the species. These systems recall the recent data of Boyse and his associates which suggest that mating preferences of mice may be controlled by the major histocompatibility complex (MHC). It seems logical to assume that the MHC did not evolve to function in transplant rejection, which is a concept accepted by too many students. 3. T cell diversification is a complicated subject to students and veteran immunologists alike, but the observation that T cell function has its phylogenetic origin at least as early as the annelld provides the rationale for such diversity in the T cell system. 4. The complement system, which to many students is a long list of proteins interacting in cascade to lyse red blood cells, gained new importance when described in invertebrates. The fact that complement activity has been described in the echinoderm suggests that complement genes may have evolved before immunoglobulln genes. 395
396
IMMUNOLOGY COURSES
VoI.I,No.4
5. Therefore, it is apparent that the origins of the immune system must not be in lower vertebrates where classical immunoglobulin first appears, but in the invertebrates where elaborate recognition systems exist, although binding proteins homologous to immunoglobulines have not been found. The fact that ~mmunoglobulins and receptors throughout phylogeny are glycoproteins is a concept that is not generally stressed to students. As the course continued the idea of a membrane bound receptor evolving into a secreted immunoglobulin was accepted as logical development. I hope that my experience with this course will help those comparative and other immunologists who are apprehensive about teaching their immunology classes from an evolutionary viewpoint. It may not only be more exciting for them, but also more profitable for the students in the class.
