Preface

This book is a collection of harmonious chapters contributed by different authors. It sets out to describe the B-cell during different stages of ontogeny and the molecular mechanisms of its antigen receptor diversity. It also discusses the main clinical and etiopathogenic aspects when it is transformed into a malignant cell.

The current book is structured into seven chapters:

The Introductory chapter describes succinctly the main features of immunoglobulins, phases of B-cell ontogeny, and B-lymphoid lineage markers, as well as diseases related to B-cell abnormalities.

Chapter 2 focuses on the molecular description of the immunogenetic mechanisms responsible for the generation of B-cell antigen receptor diversity by giving a brief overview of immunoglobulin gene organization and gene rearrangements.

Chapter 3 focuses on clinical and etiopathogenic features, prognosis, treatment, and WHO classification of B-cell lymphomas.

Chapter 4 provides a general description of B-cell lymphomagenesis.

Chapter 5 reviews the morphological, clinical, and etiopathogenic aspects, as well as the therapeutic features, of diffuse large B-cell lymphoma.

Chapter 6 describes the importance of immunophenotypic characterization of B-cell precursors using flow cytometry in the detection of minimal residual disease in acute leukemia.

Chapter 7 specifically investigates the influence of splenectomy on the composition of B-cell subpopulations.

I really hope that this book will be interesting and useful for clinicians, biologists, researchers, teachers, and graduate students of both doctoral and master's degrees in the field of immunology.

I would like to thank all the collaborators who participated in the conception of this book. I would also like to express my warmest thanks to Ms. Sandra Maljavac, Author Service Manager, for her great patience in developing this work and the coordination with the authors. I would like to thank her and the team of IntechOpen for their trust and help in making this book.

**II**

**Section 4**

Splenectomy Associated Changes in B-Cell Subsets **131**

**Chapter 7 133**

Splenectomy in Gastric Cancer: Influence of B Lymphocytes *by Chulkova Svetlana Vasilievna, Lyudmila Yuryevna Grivtsova,* 

*Ivan Sokratovich Stylidi, Nikolay Nikolayevich Tupitsyn* 

*and Zamira Magometovna Galaeva*

Section 1

B-Cells

1

Section 1 B-Cells

Chapter 1

Mourad Aribi

1. Introduction

review, see [8–10]).

2.1 Structure of Igs

2.1.1 Ig chains

2.1.2 Ig domains

3

marrow as it has been believed.

types of diseases related to B-cell abnormalities.

with each other by disulfide bridges (Figure 1).

Introductory Chapter: B-Cells

Etymologically, the "B" from B-cells, also referred to as B lymphocytes, stands from the name of bursa of Fabricius, a lymphoid organ found only in birds, as reported, in 1956, by Bruce Glick and Timothy Chang [1, 2], but not from the bone

B-cells represent about 5–15% of circulating blood lymphocytes and are responsible for the humoral immune response, as a critical component of adaptive immune system. Their roles are not limited only to the production of antigen-specific antibodies after antigen binding with high affinity via their membrane Ig but also to antigen presentation. This allows them to interact with cells involved in cellmediated immunity and to produce cytokines [3] within immunological synapses (IS) [4, 5] that they create with both CD4<sup>+</sup> T-cells [6] and CD8+ T-cells [7] (for

The current chapter presents a brief overview on Igs and phases of B-cell ontogeny and B-lymphoid lineage markers. The end of the chapter summarizes the main

The most common form of Igs in the blood has a heterodimeric structure, about approximately 150 kDa [11], with two antibody sites—paratopes—that bind to the epitope of a specific antigen, located in the fragment antigen-binding [F(ab)]. This structure is composed of two identical heavy (H) and two identical light (L) chains, these being either kappa (Lκ) or lambda (Lλ). The H and L chains are associated

Each chain of Igs is composed functionally of constant (H; CH, L; CL) and variable (H; VH, L; VL) domains. The constant region of H chain is composed of three (for IgG, IgA, IgD) or four (for IgM and IgE) constant domains, designated, respectively, CH1, CH2, CH3, and CH4. Except for IgM and IgE, the region between CH1 and CH2 domains is called the hinge "H" region, permitting flexibility in the chain [12], which is longer and more flexible in IgG3 than the other IgG subclasses [13]. Ig L chains are composed of two separate domains, each having an approximate molecular weight of 12 kDa [14]. The association of the variable domains of the H and L chains defines the site of attachment to the antigen (Figure 1).

2. Immunoglobulins: transmembrane and secreted B-cell receptors
