Chapter 3.2 lec 6.pdf

‫‪Immunology‬‬ ‫ﺗﻔﺮﯾﻎ ‪ :‬ﻣﺎﻟﻚ اﻟﻌﺒﻮﺷﻲ ‪ ،‬أﺳﻤﺎء ﺻﺮﻣﺔ ‪ ،‬ﻣﺮح ﺣﻨﺠﻞ ‪ ،‬ﻋﺒﺪ اﻟﺤﻜﯿﻢ أﺑﻮ رﺟﺎ‬ ‫ﺗﺪﻗﯿﻖ‪ :‬ﻓﺘﺤﻲ ﻣﻠﺤﻢ‬ ‫‪Key Concepts in Ab-Ag interaction‬‬ ‫...

‫‪Immunology‬‬ ‫ﺗﻔﺮﯾﻎ ‪ :‬ﻣﺎﻟﻚ اﻟﻌﺒﻮﺷﻲ ‪ ،‬أﺳﻤﺎء ﺻﺮﻣﺔ ‪ ،‬ﻣﺮح ﺣﻨﺠﻞ ‪ ،‬ﻋﺒﺪ اﻟﺤﻜﯿﻢ أﺑﻮ رﺟﺎ‬ ‫ﺗﺪﻗﯿﻖ‪ :‬ﻓﺘﺤﻲ ﻣﻠﺤﻢ‬ ‫‪Key Concepts in Ab-Ag interaction‬‬ ‫ﺑدﻧﺎ ﻧﺣﻛﻲ ﻛم ﺷﻐﻠﺔ‬ ‫ ال‪ antibody‬و اﻻﻧﺗﺟﯾن ﺑرﺗﺑطوا ب ‪) non-covalent bonds‬ﺑﻧﻌرف ﻣن اﻟﻛﯾﻣﯾﺎ اﻧو ال ‪ covalent‬ﻣن اﻗوى‬ ‫اﻟرواﺑط و اﻧﮭﺎ ‪ irreversible‬ف ﻛون اﻟرواﺑط ‪ non-covalent‬ھﺎد ﺑﺧﻠﯾﮭﺎ ‪(reversible‬‬ ‫ ﺷﻛل ال ‪ paratope‬ﺑﻛون ﻣﻛﻣل )‪ (complementary‬ﻟل ‪) epitope‬ﺷوف ﺳﻼﯾد ‪ 8‬ﻋﺎﻟﺳرﯾﻊ(‬ ‫ ال ‪ affinity‬و ‪avidity‬‬ ‫‪ Affinity‬ھﻲ اﻟﻌﻼﻗﺔ ﺑﯾن ‪ paratope‬و ‪ epitope‬و ھﻲ ﻋﺑﺎرة ﻋن ‪ non-covalent bonds‬و ﺑﺗﺗﺣدد ﻗوﺗﮭﺎ ﺑﻘوة ھﺎي‬ ‫اﻟرواﺑط اﻟﻛﯾﻣﯾﺎﺋﯾﺔ‪.‬طﺑﻌﺎ ﺑﺗﻧﻘﺎس ﺑﺎل ‪ Kd‬و ھﺎد ﺑﻌﺑر ﻋن ﻗدرة ال ‪ epitope‬و ‪ paratope‬ﻋﺎﻻﻧﻔﻛﺎك )ﻛل ﻣﺎ ﻗﻠت ﯾﻌﻧﻲ‬ ‫ﻗدرﺗﮭم ﻋﺎﻻﻧﻔﻛﺎك اﻗل ﯾﻌﻧﻲ ال ‪ affinity‬اﻛﺑر(‬ ‫‪ Avidity‬ﺑﺗﻌرب ﻋن اﻟﻌﻼﻗﺔ ﺑﯾن ‪ antibody‬ﻣﻊ اﻻﻧﺗﺟﯾن و ھﺎي ﺑﺗﻌﺗﻣد ﻋﻠﻰ ‪:‬‬ ‫‪.1‬ال ‪ affinity‬ﯾﻌﻧﻲ ﻛل ﻣﺎ زادت ﻗوة اﻻرﺗﺑﺎط ﺑﯾن ال ‪ epitope‬و ‪ paratope‬ﻛﺎﻧت ال ‪ avidity‬اﻛﺑر‬ ‫‪.2‬ال ‪ valency‬و ھﻲ ﺑﺎﺧﺗﺻﺎر )ﻛم ‪ paratope‬ارﺗﺑط ب‪ (epitope‬ﻣﺛﻼ ﻟو ارﺗﺑط اﻧﺗﺟﯾن ب ‪ antibody‬و ﻛﺎن‬ ‫اﻻرﺗﺑﺎط ﺑﯾﻧﮭم ھو ‪ paratope‬واﺣد ﻣﻊ ‪ epitope‬واﺣد رح ﺗﻛون ال ‪ avidity‬اﻗل ﻣن ‪ antibody‬ارﺗﺑط ﺑﺎﻧﺗﺟﯾن و‬ ‫ﻛﺎن اﻻرﺗﺑﺎط ﺑﯾﻧﮭم ‪ 10 epitope‬ﻣﻊ ‪10 paratope‬‬ Key Concepts in Ab-Ag interaction 1. Antibody (Ab) form multiple non-covalent bonds with antigen=> Reversible - Attractive forces (H bonds, electrostatic bonds, van der Waals forces, & hydrophobic forces) => High affinity interaction 2. The Ag-binding sites of an Ab are complementary to the conformation of Ag determinants (epitopes) of an Ag. 3. Affinity vs. Avidity forA b ó A g Affinity => A measure of the strength of interaction between an Ag-binding site and its epitope => Kd, dissociation constant; small Kd => stronger affinity Avidity => The overall strength of A b ó A g => Affinity & the valency of interactions 3 Affinity and avidity ‫ راﺑط ب اﻛﺗر‬AB ‫ھون‬ ‫ﻣش ﻣوﻧﻣر اﻧﻣﺎ‬AB ‫ھون ال‬ ‫ ﺑﻧﺳﻣﯾﮫ‬epitope ‫ﻣن‬ multivalent ‫وﻋﻠﯾﮫ ﻛﺗﯾر‬pentamer - Can bind with 2 ‫ﺑﺗﻘدر ﺗرﺗﺑط‬bindind sites epitopes up to 10 epitopes ‫ ﻛﺎﻣل‬AB ‫ھون ﻋﻧﺎ‬ ‫ھون ﻋﻧﺎ ﺟزء ﻣن ال‬ ‫ ﯾوﺟد‬fab ‫ﺑس‬AB one binding ‫ﺑس‬ site ‫ اﻟﻣرﺗﺑطﯾن‬epitope ‫ﻋدد ال‬ binding ‫ﻛل ﻣﺎ ﻛﺎن ﻋﻧدي‬ ‫ اﻟﻛﻠﻲ‬epitopes ‫ﻋدد ال‬ ‫اﻛﺗر ﻛﺎن اﻟﺗﻔﺎﻋل ﺛﺎﺑت‬sites constant ‫ﻛم ﺑﺿل اﻟرﯾﺎﻛﺷن‬ ‫اﻛﺗر‬ one ‫ ﻻﻧﮫ ﻋﻧﺎ‬Affinity epitope Avidity = more than one Multivalent binding between antibody and antigen (avidity or functional affinity) results in a considerable increase in stability as measured by the equilibrium constant, compared with simple monovalent binding. 2019-2020 Immunology 7105306 23 Ab variability The hypervariable region (HV 1-3) are separated in the primary structure, but come together in the tertiary structure where they form antigen binding site. Alias Complementary Determining Region or CDR 1-3 -The HV regions form loops at the end of Ig domain - The intervening framework region (FR 1-4) make up the rest of the structure epitope ‫ ﻟل‬specific ‫ وﺑﺗﻛون‬paratope ‫ ھﻲ اﻟﻠﻲ ﺑﺗﺷﻛل ال‬variable site ‫ال‬ 3 ‫ ﻋﻧﺎ‬hypervariable region ‫ واﻟﺳﺑب ﺑذﻟك وﺟود ال‬, ‫وھﻲ ﺳﺑﺳﻔك ﻻﻧﮭﺎ ﻣﺗﻐﯾرة‬ ‫و ﻣﺗل ﻣﺎ ﺷﺎﯾﻔﯾن ﺑﺎﻟرﺳﻣﮫ ﻋﺎﻟﯾﻣن ھﻣﺎ اﻟﻠﻲ ﻟوﻧﮭم اﺣﻣر‬HV1-2-3 ‫ﻣﻧﺎطق ﺑﻧرﻣزﻟﮭم ب‬ ter9ary ‫ ﺑﺎل‬, ‫ اﻣﺎ اﻻﺻﻔر ﻓﮭو ﻣش ﻣﺗﻐﯾر‬-‫ﻓﺑﻛوﻧو ﻣﻔﺻوﻟﯾن ﺑﺎﻟﺑراﯾﻣري ﺳﺗرﻛﺗﺷر‬ ‫اﻟﻠﻲ ﺑﻧﺳﻣﯾﮫ‬an9gen binding site ‫ ﺑرﺗﺑطو ﻣﻊ ﺑﻌض وﺑﺷﻛﻠو ال‬structure (3D) alias complementary determining region CDR1-3 the ‫ اﻟﻠﻲ ﺑﺟﻣﻌﮭم طﯾب ؟ اﻟﻠﻲ ھو اﻻﺷﻲ اﻻﺻﻔر وﺑﻧﺳﻣﻲ‬structure ‫ﺷو ال‬ intervening framework region FR1-4 5 ‫‪Antibody structural variation‬‬ ‫ﺑدﻧﺎ ﻧﺣﻛﻲ ﻋن اﺧﺗﻼﻓﺎت ﺑﺎل ‪ structures‬ﺗﺎﻋت ال ‪antibodies‬‬ ‫‪ :Isotypes.1‬ھون ﺑﺣﻛﻲ ﻋن اﻻﺧﺗﻼف ﺑﺎل ‪ class‬و ﺣﻛﯾﻧﺎﻋﻧﮭن زي ‪ IgM,IgG(1-4),IgD,IgA(1,2),IgE‬طﺑﻌﺎ‬ ‫اﻻﺧﺗﻼف ﺑﺎل ‪heavy chains‬‬ ‫‪ :allotypes.2‬ﺑدﻧﺎ ﻧﺣﻛﻲ ﻋن ﻧﻔس ال ‪ class‬ﺑس ﻋﻧد اﺷﺧﺎص ﻣﺧﺗﻠﻔﯾن )ھﺎن ﺑﻛون ﻣﺛﻼ ال ‪ IgM‬ﻋﻧدي ﺷﺑﮫ اﻟﻠﻲ ﻋﻧدك‬ ‫ﺑس ﻓﻲ ﻓروﻗﺎت ‪ immunological‬ﺻﻐﯾرة )ﺣﺗﻰ ال ‪ v region‬ﺗﻘرﯾﺑﺎ ﻧﻔﺳﮭﺎ دﻻﻟﺔ اﻧﮭﺎ ﺑﺗﻘﺎوم ﻧﻔس اﻻﻧﺗﺟﯾن طﺑﻌﺎ ﻣﻊ‬ ‫ﺗﻐﯾرات ﺑﺳﯾطﺔ (‬ ‫‪ :Idiotypes.3‬ھﺎن ﺑﺣﻛﻲ ﻋن اﻧو ﻣن ﻧﻔس ال ‪ class‬ﺑس ال ‪ v region‬ﻣﺗﻐﯾرة ﻻﻧو ﺑﻘﺎوم اﻧﺗﺟﯾﻧﺎت ﻣﺧﺗﻠﻔﺔ‬ ‫ﺑﺎﺧﺗﺻﺎر ‪ isotypes‬اﺧﺗﻼف ﺑﺎل ‪ Allotypes. class‬ﻧﻔس ال ‪ class & v-region‬ﺑس اﺧﺗﻼﻓﺎت ﺑﺳﯾطﺔ ﻻﻧﮭﺎ ﻣش ﻣن‬ ‫ﻧﻔس اﻟﺷﺧص‪ Idiotypes.‬ﻧﻔس ال ‪ class‬ﺑس ‪ v region‬اﺧﺗﻠﻔت‬  Antibody structural variation Isotypes: have different heavy chains. They are represent classes ofAb. Allotypes: have the same constant regions with minor, but immunologic differences. Different individuals have different allotypes. Idiotypes: Abs that recognize different specific epitopes. Each idiotype is composed of several idiotypes or combining sites. Heavy chain isotypes are encoded by μ, δ, γ3, γ1,α1, γ2, γ4, α2, and ε genes on chromosome 14. The single κ and multiple λ isotypes are encoded by Cκ and Cλ genes on chromosomes 2 and 22, respectively. ‫ ھدول ﺑﻧﻔس اﻟﺷﺧص‬IgE IgD ‫ وﻛﻣﺎن ال‬IgA 1-2 ‫ و‬IgM ‫ وﻛﻣﺎن ال‬IgE1-2-3-4 ‫ ﻣﺗل ﻣﺎ ﻛﻧﺎ ﻧﺣﻛﻲ‬:isotypes -1 ‫ اﻟﻠﻲ ﺣﻛﯾﻧﺎھم‬9 ‫ال‬IgA –M-E ‫ واﻟﻔرق ازا‬individual ‫ ﺑﻧﻔس ال‬AB ‫ ھﻣﺎ ﺑﺎﺧﺗﺻﺎر‬isotopes ‫ﺑﻧﺳﻣﯾﮭم‬ , ‫ﺗﻘرﯾﺑﺎ و‬CONSTANT R ‫ ھﻣﺎ ﻋﻧدھم ﻧﻔس ال‬IgA 1 ‫ اﻟﻣوﺟود ﻋﻧدي وﻋﻧد زﻣﯾﻠﻲ ال‬ab ‫ ال‬allotypes -2 immunologic difference Staph aureus ‫ ﺿﺪ ال‬IgM ‫ أو‬E.coli ‫ ﺿﺪ ال‬IgM ‫ ﻓﻤﻤﻜﻦ‬Ag ‫ ﺳﺒﺴﻔﻚ ل‬AB ‫ ﻣﺶ اﺣﻨﺎ ﺑﻨﻨﺘﺞ‬idiotype -3  Complementary interactions between Ag- binding sites and their epitopes Epitope binds to its binding site Each site is specific to its epitope ( its complementary to its Ag) ‫ ﺑرﺑط ع‬epitope ‫ﻣﺛل ﻣﺎ ﺷﺎﯾﻔﯾن ﻛﯾف ﻛل‬ ‫ ﻣﻌﯾن و ﺑﻛون ﺧﺎص ﻓﯾﮫ‬paratope 8  Specificity, Cross-reactivity & non-reactivity of AbóAg ‫ ﻋﻼﻗﺎت ﺑﺘﺨﺘﻠﻒ ﺣﺴﺐ ﻗﻮﺗﮭﺎ‬3 ‫ ﻓﻲ‬antigen ‫ وال‬antibody ‫ﺑﯿﻦ‬ ‫ ﺑﺎﻻﻧﺘﺠﯿﻦ ﯾﻌﻨﻲ ال‬epitope ‫ ﻋﻠﻰ‬100% ‫ راﻛﺐ ﺑﺎﻟﺰﺑﻂ‬antibody‫ ﻋﺎل‬paratope ‫ و ھﺎد ﺑﻜﻮن ﻛﻞ‬: Specificity.1 100% ‫ ﺑﺘﻜﻮن‬avidity ‫ و ال‬100% ‫ ﺑﺘﻜﻮن‬paratope ‫ ﻋﻜﻞ‬affinity ‫ ﺑﺘﻨﻘﺴﻢ ل‬antibody ‫ اﻟﻤﻮﺟﻮدات ﻋﺎل‬paratope ‫ ھﻮن ال‬:Cross-reaction.2 (anti Y ‫ )ﻣﺜﻞ‬epitope ‫ ﻋﺎل‬100% ‫ ﺑﺮﺑﻂ ﺑﺸﻜﻞ‬Paratope (anti X ‫ )ﻣﺜﻞ‬epitope ‫ ﺑﺮﺑﻂ ﺑﺸﻜﻞ ﺟﺰﺋﻲ ﻋﺎل‬Paratope 100% ‫ اﻗﻞ ﻣﻦ‬avidity ‫ ﻣﺘﻐﯿﺮة اﻣﺎ ال‬affinity ‫ ﺣﺘﻜﻮن ال‬cross ‫ طﺒﻌﺎ ﺑﺎل‬.anti Z ‫ ﻣﺎ ﺑﺮﺑﻂ ﺑﺎﻟﻤﺮة ﻣﺜﻞ‬Paratope ‫ ﺑﺘﻜﻮن‬avidity ‫ و‬affinity ‫ ف ﺑﺎﻟﺘﺎﻟﻲ ﺑﻨﻘﺪر ﻧﻘﻮل ال‬paratope ‫ ﺑﻘﺪر ﯾﺮﺑﻂ ﻣﻊ‬epitope ‫ ھﻮن ﺑﻜﻮن وﻻ‬:No reaction.3 0% 1 ‫ﺣﺎﻟﺔ‬ 2 ‫ﺣﺎﻟﺔ‬ 3 ‫ﺣﺎﻟﺔ‬  Specificity, Cross-reactivity & non-reactivity of AbóAg Antiserum specificity results from the action of a population of individual antibody molecules (anti-X, anti-Y, anti-Z) directed against different epitopes (X, Y, Z) on the same or different antigen molecules. Antigen A (AgA) and antigen B (AgB) have epitope Y in common. Antiserum raised against AgA (anti-XYZ) not only reacts specifically with AgA, but cross- reacts with AgB (through recognition of epitopes Y and X′). The antiserum gives no reaction with AgC because there are no shared epitopes. immunology 7105306 10  Q&As The figure shows two cases of ab/ag interaction, answer the following 1. Affinity is affected in every epitope/paratope except A. Anti X B. Anti Y C. Anti Z D. A+B 2. Which sentence is true (you can choose more than one) A. The avidity in case B is higher than in case A B. The avidity in case B is lower than in case A C. The valence in case A is 3 D. The plasma cell in case A is more likely to get clonal selection than in B Case A Case B Anti X Anti Y Anti Z 1. B 2. B&C&D ‫‪The Nature of Ag determinants‬‬ ‫ھﺳﺎ اﻻﻧﺗﺟﯾن ﺑﺎﻟﻐﺎﻟب ﺑﻛون ‪ protein‬و ﻣﻣﻛن ﯾﺗﻌرض ل ‪ denaturation‬ﺳواء ﺑﺎﻟﺣرارة او ‪ ph‬او او ‪...‬و طﺑﻌﺎ ال‬ ‫‪ denaturation‬ﺑﺣول اﻻﻧﺗﺟﯾن ﻣن ‪ 3d structure‬ل ‪linear‬‬ ‫ﻓﻲ ﻋﻧﺎ ﻋدة أﻧواع ﻣن ال ‪ epitopes‬ﻣن ھﺎي اﻟﻧﺎﺣﯾﺔ‪:‬‬ ‫‪ : Conformational.1‬ھﺎد ﺑﺗﻌرف ﻋﻠﯾﮫ ال ‪ antibody‬ﻟﻣﺎ ﯾﻛون ال ‪ epitope‬ﺑﺎل ‪3d structure‬و ﻟو ﻋﻣﻠﺗﻠﮫ‬ ‫‪ denaturation‬ﺑﺑطل ﯾﺗﻌرف )ﻣﺛل اﻟﺣﺎﻟﺔ ‪(A‬‬ ‫‪) : Linear.2‬اﻟﺣﺎﻟﺔ ‪ (B‬ھﺎن ال ‪ antibody‬ﻣﺛﻼ ﻋرف ﯾﺗﻌرف ﻋﺎﻻزرق ﺑﺎﻟﺣﺎﻟﺗﯾن )‪ (linear & 3D‬اﻣﺎ اﻟﺑرﺗﻘﺎﻟﻲ ﻣﺛﻼ‬ ‫ﻣﺎ ﻛﺎن ﻗﺎدر ﯾرﺑط ﻋﺎل ‪ 3D‬ﺑس ﻟﻣﺎ ﺻﺎر ‪ linear‬رﺑط‬ ‫‪ :Neoantigenic.3‬ھﺎن ﻛﺎن ﺑﻠزم ال ‪ epitope‬ﻣﻌﺎﻟﺟﺔ ﻟﺣد ﻣﺎ ﻗدر ال ‪ antibody‬ﯾﺗﻌرف )ﺣﺎﻟﺔ ‪(C‬‬ The Nature of Ag determinants Antigenic determinants (shown in orange, red, and blue) may depend on protein folding (conformation) as well as on primary structure. Some determinants are accessible in native proteins and are lost on denaturation (A), whereas others are exposed only on protein unfolding (B). Neodeterminants arise from postsynthetic modifications such as peptide bond cleavage (C). immunology 7105306 14  ‫‪Antibody & otherAntigen- Recognizing Molecules‬‬ ‫ھﺴﺎ ﻛﻞ ﺣﻜﯿﻨﺎ ﻛﺎن ﻋﻦ ال ‪ antibodies‬اﻟﻠﻲ ھﻢ ‪ BCR‬ھﺴﺎ ﺑﺪﻧﺎ ﻧﺤﻜﻲ ﺑﺸﻜﻞ ﺳﺮﯾﻊ ﻋﻦ ال ‪ TCR‬اﻟﻠﻲ ﻋﻠﻰ ‪ T cells‬و ال‬ ‫‪) MHC‬وﯾﻦ ھﺪول؟ ‪...‬اﻟﻠﻲ ﺑﻌﻤﻠﻮا ‪ antigen presenting‬ﻟﻞ‪ (TCR‬و ﺑﺪﻧﺎ ﻧﺤﻜﻲ ﻋﻦ أوﺟﮫ اﻟﻤﻘﺎرﻧﺔ‬ ‫‪1. Antigen binding site‬‬ ‫ ‪ :Antibody‬ﻣﺜﻞ ﻣﺎ ﺑﻨﻌﺮف اﻧﻮ ال ‪ paratope‬ﻣﻮﺟﻮد ﺑﺎل ‪ V region‬و ھﺎي اﻟﻤﻨﻄﻘﺔ ﻓﯿﮭﺎ ‪ 3CDRs‬ﻋﻠﻰ ‪ Vh‬و‬ ‫‪ 3CDRs‬ﻋﻠﻰ ‪) VL‬ارﺟﻌﻮا ﻛﻢ ﺳﻼﯾﺪ ورا ﻟﺘﺘﺬﻛﺮوا ال ‪(CDR‬‬ ‫ ‪ :TCR‬ذاﻛﺮﯾﻦ ﻟﻤﺎ ﺣﻜﯿﻨﺎ ﺑﺘﺸﺎﺑﺘﺮ ‪ 2‬ﺳﻼﯾﺪ ‪ 47‬ﻋﻦ ال ‪ T delta gamma‬و ‪ T alpha beta‬ھﺴﺎ اﻟﺘﺴﻤﯿﺔ اﺟﺖ ﻣﻦ أﺳﻤﺎء‬ ‫اﻟﺴﻼﺳﻞ ﺑﺎل‪) TCR‬رﻛﺰ ﺑﺎﻟﺼﻮرة( ھﺴﺎ ﻟﻮ اﺧﺬﻧﺎ ال ‪ TCR‬اﻟﻤﻮﺟﻮد ﻋﻠﻰ ‪ T alpha beta‬رح ﻧﻼﻗﻲ اﻧﻮ ﻓﻲ ‪3CDRs‬‬ ‫ﻋﻠﻰ ال ‪ V alpha‬و ‪ 3CDRs‬ﻋﻠﻰ ‪V beta‬‬ ‫ ‪ :MHC‬ھﺎن ﺑﻜﻮن ال‪ binding site‬زي ﺟﯿﺒﺔ ﻣﺘﻜﻮﻧﺔ ﻣﻦ ﺳﻠﺴﻠﺘﯿﻦ )‪ alpha1 & alpha2‬ﺑﺎل ‪ MHCI‬و ‪alpha1‬‬ ‫‪ beta1‬ﺑﺎل ‪(MHCII‬‬ ‫‪AB‬‬  Antibody & otherAntigen- Recognizing Molecules 2. Nature of antigen processing ‫ ھﯿﻚ ﺟﺎي ﻣﻦ ﺑﺮا ﻋﻄﻮل ﺑﺘﻌﺮف ﻋﻠﯿﮫ دون اﻟﺤﺎﺟﺔ ل‬macromolecule ‫ ﺑﻜﻮن أي‬:Antibody (intact ‫)ﺑﻨﺴﻤﯿﮫ‬ MHC ‫ ﺻﻐﯿﺮة و ﺑﻌﺪھﺎ ﯾﻘﺪﻣﻠﻮ ﯾﺎه ال‬peptides ‫ ھﺎد ﻣﺪﻟﻊ ﺑﺪو اﻟﺒﺮوﺗﯿﻦ ﯾﺘﻘﻄﻊ ل‬: TCR TCR ‫ اﻟﻠﻲ ﺣﺘﺸﻮﻓﮭﺎ ال‬peptides ‫ ﺑﺤﻤﻞ ال‬:MHC 3. Antigenic determinant recognized (conformational) 3D ‫ او‬linear ‫ ﻣﺜﻞ ﻣﺎ ﻗﻠﻨﺎ ﺑﻘﺪر ﯾﺮﺑﻂ ب‬:Antibody 2-3 amino acids ‫ و أﻗﺼﺎه‬linear ‫ ﺑﻜﻮن ﺑﺲ‬:TCR peptides ‫ ف ﺣﯿﻜﻮن ﻗﻄﻊ ﺻﻐﯿﺮة ﻣﻦ‬TCR ‫ ﺑﺤﻤﻞ ﻧﻔﺲ اﻻﻧﺘﺠﯿﻦ اﻟﻠﻲ ﺑﺪو ﯾﻔﺮﺟﯿﮫ ل‬: MHC 4. Affinity of antigen binding secondary lymph ‫ ﻻﻧﻮ ﺑﺎل‬immune response ‫ و ﺑﺘﺰﯾﺪ وﻗﺖ ال‬10^-11 ‫ اﻟﻰ‬10^-7 ‫ ﺑﻜﻮن‬: Antibody affinity ‫ ھﺎد ﺑﺰﯾﺪ ال‬germinal center ‫ ﺑﺘﺼﯿﺮ ﺑﺎل‬affinity maturation ‫ ﺑﻨﻌﺮف اﻧﻮ ﺑﺼﯿﺮ اﺷﻲ اﺳﻤﻮ‬organs 10^-7 ‫ اﻟﻰ‬10^-5 :TCR extremely stable binding ‫ و ﺑﻤﺘﺎز ب‬10^-9 ‫ اﻟﻰ‬10^-6 :MHC ‫ﻛﻠو ﻣﻠﺧص ﺑﺎﻟﺟدول اﻟﻠﻲ ﺑﺎﻟﺳﻼﯾد اﻟﺑﻌد‬ Antibody & other Antigen- Recognizing Molecules immunology 7105306 17  ‫‪Flexibility of A b ó A g interactions‬‬ ‫ھﺎن ﺑﺣﻛﻲ ﻋن ﻣﻧطﻘﺔ اﺳﻣﮭﺎ ال ‪ hinge‬و ھﺎي ﺑﺗﻛون ﺷﺑﮫ اﻟزﻣﺑرك ﺣرة اﻟﺣرﻛﺔ ف ﺑﺗﻣﻛن ﻣن ﺧﻼﻟﮭﺎ ال ‪ antibody‬اﻧو‬ ‫ﯾﻣﺳك ‪ epitopes‬ﺑﻌﯾدة ﻋن ﺑﻌﺿﮭﺎ )ﻟدرﺟﺔ اﻧو ‪ antibody‬واﺣد ﺑﻘدر ﯾرﺑط ع ‪ epitope‬ﻣن ﺧﻠﯾﺔ و ﻛﻣﺎن ‪ epitope‬ﻣن‬ ‫ﺧﻠﯾﺔ ﺛﺎﻧﯾﺔ و ھﺎد ﺑﻔﯾدﻧﺎ ﺑﻌﻠم اﻻﻣﺻﺎل(‬ ‫طﺑﻌﺎ ھﺎي اﻟﺧﺎﺻﯾﺔ )اﻧو ال ‪ antibody‬ﯾﻘدر ﯾﻣﺳك ﺑﺄﻛﺛر ﻣن ﺧﻠﯾﺔ( ﺑﺳﺗﺧدﻣوھﺎ ﺑﺎل ‪: blood test‬‬ ‫)ﻣﺛﻼ ﻋﻧﺎ ﻋﯾﻧﺔ دم ﺣطﯾﻧﺎ ﻋﻠﯾﮭﺎ ‪ antiA‬ﺻﺎرت ﺗﺗﻛﺗل و ﺣطﯾﻧﺎ ‪ antiB‬ﻣﺎﺻﺎر اﺷﻲ ﻓﺑﻔﮭم اﻧو ال ‪ antiA‬ﻗدر ﯾرﺑط ﻣﻊ اﻛﺛر‬ ‫ﻣن ﺧﻠﯾﺔ ﻋﺷﺎن ھﯾك ﺗﻛﺗ ّل ف ﻣوﺟود اﻧﺗﺟﯾن ‪ A‬اﻣﺎ اﻧﺗﺟﯾن‪ B‬ﻣش ﻣوﺟود ﻓﺑﻌرف اﻧو زﻣرة دﻣو ‪(A‬‬ ‫‪18‬‬  The Development of monoclonal Ab : ‫ﺑدﻧﺎ ﻧﺣﻛﻲ ﻋن ﻣﺻطﻠﺣﯾن‬ ‫ ﻣﺧﺗﻠﻔﺔ ﻗﺎدرة ﻋﻠﻰ اﻟرﺑط ﺑﻧﻔس اﻻﻧﺗﺟﯾن )ھﺳﺎ ﻻﻧو‬B cells ‫ ﻣن‬an9bodies ‫ ھو ﻋﺑﺎرة ﻋن ﻋدة‬: Polyclonal an9bodies ‫ ﺛﺎﻧﻲ ﯾرﺑط ع‬an9body ‫ ﻣﻌﯾن و‬epitope ‫ ﯾرﺑط ﻋﻠﻰ‬an9body ‫ ﻋدﯾدة و ﻣﺧﺗﻠﻔﺔ ف ﻣﻣﻛن اﻧو‬epitopes ‫اﻻﻧﺗﺟﯾن ﻋﻠﯾﮫ‬ (epitope ‫ ﺑرﺑطوا ﻋﺎﻧﺗﺟﯾن واﺣد ﺑس ﻣش ﻋﻧﻔس ال‬an9bodies ‫ ﺛﺎﻧﻲ ﻋﻧﻔس اﻻﻧﺗﺟﯾن( )ﺑﺎﺧﺗﺻﺎر ﻋدة‬epitope plasma cell ‫ ﺷو ﯾﻌﻧﻲ ؟ ﯾﻌﻧﻲ ﻣن ﻧﻔس ال‬epitope ‫ ﺑرﺑطوا ﻋﻧﻔس ال‬an9bodies ‫ ھون ﻋدة‬:Monoclonal an9body ‫ھﺳﺎ ھﺎد اﻻﻛﺗﺷﺎف اﻟو ﻋدة ﺗطﺑﯾﻘﺎت‬ Unlimited production of unique Ab for a specificAg => Revolutionize Immunology & other fields Its Applications: - Identification of phenotypic markers - Immunodiagnosis & Immunotherapy 19 - Tumor diagnosis & therapy ‫‪The Development of monoclonal Ab-II‬‬ ‫ﺑدﻧﺎ ﻧﺣﻛﻲ ﻋن طرﯾﻘﺔ اﻟﺗﺻﻧﯾﻊ ‪:‬‬ ‫‪.1‬ﺑﻧزرع اﻻﻧﺗﺟﯾن ﻓﻲ ﻛﺎﺋن ﺣﻲ )ﺑﺗﻧﺷط ال ‪ APC‬ﺑﻌدھﺎ ‪T cells‬‬ ‫اﻟﻠﻲ ﺑﺗﻧﺷط ‪ (B cell‬ﻧﺗﺞ ﻋﻧﺎ ‪ plasma cell‬ﺑﺗﻧﺗﺞ‬ ‫ال‪antibody‬‬ ‫‪.2‬اﺣﻧﺎ ﺑدﻧﺎ ﯾﺎھﺎ ﺗﺿل ﻛﻣﺻدر ﺧﺎرج ﺟﺳم اﻟﺣﯾوان ف ﺑﻧطﻠﻊ‬ ‫ﻋﯾﻧﺔ ﻣﻧﮫ و ﺑﻧﻌزل ال ‪) B cells‬ﺳﻼﯾد‪ 56‬ﺗﺷﺎﺑﺗر‪(2‬‬ ‫‪.3‬اذا ﺿﻠت ﺑرا اﻟﺟﺳم اﺣﺗﻣﺎل ﺗﻣوت ﺑﺳرﻋﺔ ف‬ ‫ﺑﻧدﻣﺟﮭﺎ)‪ (fusion‬ﻣﻊ ‪) cancerous cell‬ﺑﻣﺗﺎزوا ﺑﺎﻧﻘﺳﺎﻣﺎت‬ ‫ﺳرﯾﻌﺔ و ﺣﯾﺎة طوﯾﻠﺔ(‬ ‫‪.4‬ھﺳﺎ ﻓﻲ ﺧﻼﯾﺎ ﻣﺎ ﺻرﻟﮭﺎ ‪ fusion‬ف ﺑدﻧﺎ ﻧﻘﺗﻠﮭﺎ ﻋن طرﯾق‬ ‫زرع ال‪ mixture‬ﺟوا وﺳط ﺑﺳﻣﺢ ﺑﺣﯾﺎة ال ‪fused cells‬‬ ‫‪only‬‬ ‫‪.5‬ھﺳﺎ ﺑﻧﻌزل اﻟﺧﻼﯾﺎ اﻟﻠﻲ ﺿﻠت ﻣﻌﻧﺎ ﺣﺳب اي اﻧﺗﺟﯾن ﺑﺗﻌﺎﻟﺞ‬ ‫)ﺳﻼﯾد ‪ 56‬ﺗﺷﺎﺑﺗر ‪(2‬‬ ‫‪.6‬ﺑﻧﻣﻲ ﻛل ﺧﻠﯾﺔ ﺑﺗﻧﺗﺞ ‪ antibody‬ﻣﻌﯾن و ﺑﺳﺣب اﻓرازاﺗﮭﺎ‬ ‫)ﻣن ﺑﯾﻧﮭﺎ ‪ (antibody‬و ﻣن ھون ﺑﻛون ﺟﺑت‬ ‫‪monoclonal antibody‬‬ ‫‪Immunodiagnosis- ELISA‬‬ ‫طب ھﺳﺎ ﺷﻔﻧﺎ ﻛم ﺻﻌب ﻧطﻠﻊ ال ‪ monoclonal antibodies‬ھﺳﺎ ﺑدﻧﺎ ﻧﻌطﯾﮭم ﻟﻠﻧﺎس ‪..‬ھل ﻣﻌﻘول اﻋطﻲ ال ‪ serum‬ﻟواﺣد‬ ‫ﻋﻧدو ‪ antibody‬اﺻﻼ؟ ﻻ ‪.‬طب ﻛﯾف ﺑدﻧﺎ ﻧﻌرف اذا ﻋﻧدو ‪ antibodies‬ﻻﻧﺗﺟﯾن ﻣﻌﯾن ؟ ﻋن طرﯾق ‪immunodiagnosis‬‬ ‫ﺑﺎﺳﺗﺧدام ‪ ELISA‬و ھﺎد ﺑﻣﺷﻲ ﻋﺎﻟﻣﺑدأ اﻟﺗﺎﻟﻲ ‪:‬‬ ‫‪.1‬ﺑﻌﻣل ﻟوﻋﺎء ‪ coating‬ﺑﺎﻻﻧﺗﺟﯾن اﻟﻠﻲ ﺑدي اﻋرف ھل ﻋﻧدو ‪ antibody‬او ﻻ‬ ‫‪.2‬ﺑﺟﯾب ﻋﯾﻧﺔ ﻣن اﻟﺷﺧص و ﺑﺣﻠل ﻣرﻛﺑﺎت اﻟدم ﻟﺣد ﻣﺎ اﺣﺻل ﻋﺎل ‪) antibodies‬ھﺎي ﻛﻠﻠل اﻟﻠﻲ ﺑﺎﻟﺟﺳم ﻣش ﻻﻧﺗﺟﯾن ﻣﻌﯾن(‬ ‫‪.3‬ﺑﺣط ﻋﯾﻧﺔ ال ‪ antibodies‬ﺑﺎﻟوﻋﺎء اﻟﻠﻲ ﻋﻣﻠﻧﺎﻟو ‪) coating‬طﺑﻌﺎ اﻟﻠﻲ ﺑرﺑط ھو ال ‪ antibody‬اﻟﻠﻲ ﺑرﻛب ﻋﺎﻻﻧﺗﺟﯾن(‬ ‫‪.4‬ﺑﻌﻣل ‪ washing‬ف أي اﺷﻲ ﻣش راﺑط ﺑﺎﻻﻧﺗﺟﯾن ﺑروح‬ ‫‪.5‬ﺑﺟﯾب ﺟزيء ﻣﻛون ﻣن ﺟزيء ﺑرﺑط ﻋﺎل ‪)antibody‬زي ‪ antibody‬ﻟل‪ (antibody‬و ھﺎد اﻟﺟزيء ﻋﻠﯾﮫ اﻧزﯾم ھﺎد ﻛﻠو‬ ‫ﺑﺳﻣﯾﮫ ‪ligand‬‬ ‫‪.6‬ﺑﻌﻣل ‪ washing‬ف أي ‪ ligand‬ﻣﺎ رﺑط ب‪ antibody‬ﺑروح‬ ‫‪.7‬ﺑﺣط ‪ chromogen‬وھﺎد زي ﻣﺎدة ﻟﻣﺎ ﺗﺗﻌرض ﻟﻼﻧزﯾم ﺑﺗﻐﯾر ﻟوﻧﮭﺎ‬ ‫‪.8‬طﺑﻌﺎ اذا ﻣﺎ ﺗﻐﯾر اﻟﻠون ﻣﻌﻧﺎھﺎ ﻣﺎ ﻓﻲ ‪ antibody‬اذا ﺗﻐﯾر ﺷوي ﺻﻐﯾرة ﻓﻲ‪ antibodies‬ﺑﺗراﻛﯾز ﻗﻠﯾﻠﺔ و ﻛل ﻣﺎ زاد‬ ‫اﻟﺗﻐﯾﯾرﺑﻛون ﺗرﻛﯾز ال ‪antibodies‬‬  ‫‪Immunodiagnosis- ELISA‬‬ ‫ﺣطﯾﻧﺎ ‪ chromogen‬و ھﺎد‬ ‫ﺑﺗﻐﯾر ﻟوﻧﮫ ﻟﻣﺎ ﯾﺗﻌرض ﻻﻧزﯾم‬ ‫ﺣطﯾﻧﺎ ﻋﯾﻧﺔ اﻟدم و ﺑس ال‬ ‫ﺑﻧﻼﺣظ اﻧو ﺑﻧﻘدر ﻧﻼﻗﻲ ال ‪concentra6on‬‬ ‫‪ antibody‬اﻟﻠﻲ ﺑدﻧﺎ ﯾﺎه رﺑط‬ ‫ﺣﺳب ﻛﻣﯾﺔ اﻟﺗﻐﯾر ﻓﻲ اﻟﻠون‬ ‫‪Enzyme‬‬ ‫‪Ligand‬‬ ‫‪Absorption‬‬ ‫‪Wash‬‬ ‫‪Wash‬‬ ‫‪Antibody concentration‬‬ ‫‪.1‬ﺑﻧﻌﻣل ‪ coating‬ﺑﺎﻻﻧﺗﺟﯾن‬ ‫ﻋﻣﻠﻧﺎ ‪ washing‬ﻋﺷﺎن أي ﻣواد‬ ‫ھون ﺣطﯾﻧﺎ ال ‪ ligand‬و‬ ‫ﺛﺎﻧﯾﺔ ﺗروح و ﯾﺿل اﻟراﺑط ﺑس‬ ‫ﺑﻌدھﺎ ‪ washing‬ﻋﺷﺎن أي‬ ‫اﻧزﯾﻣﺎت ﻣﺎ رﺑطت ﺗروح‬ Immunodiagnosis- ELISA immunology 7105306 23 ‫‪Immunoprecipitation‬‬ ‫ھﺎن ﺑدﻧﺎ ﻧﻌﻣل ‪ detection‬ﻻﻧﺗﺟﯾن ﻣﻌﯾن)ﻧﻘول اﻻﻧﺗﺟﯾن‬ ‫اﻟﻣرﺑﻊ(‬ ‫‪.1‬رح ﻧﺿﯾف ‪ antibody‬ﻣﻧﺎﺳب ﻟﻼﻧﺗﺟﯾن‬ ‫‪.2‬ﺑﻧﺣط اﺷﻲ اﺳﻣو ‪co-precipitating reagents‬‬ ‫ﺑﺗﺳﺎﻋد اﻧو ﯾﺗرﺳب‬ ‫‪.3‬ﻟﻣﺎ ﯾرﺗﺑطوا رح ﯾﻛون ﺣﺟﻣﮭم و ﻛﺗﻠﺗﮭم اﻛﺑر ف‬ ‫ﺑﻧﻘدر ﻧﻌزﻟﮭم ﺑﺎﻟطرد اﻟﻣرﻛزي ‪ centrifugation‬و‬ ‫ﺑﻧطوﻟﮭم ﻣن اﻟﻌﯾﻧﺔ‬ ‫‪.4‬ﺑﻧﺣطﮭم ع ‪ SDS gel‬و ھﺎد ﺑﻌﻣل ﻋﻔﺻل‬ ‫اﻟﺑروﺗﯾﻧﺎت ﻋن ﺑﻌض‬ ‫‪.5‬ﺑﻛﺷف ﻋن اﻟﺑروﺗﯾﻧﺎت ﺑﺎﺷﻲ اﺳﻣو‬ ‫‪ immunoblotting‬ﺑﺎﻟﺳﻼﯾد اﻟﺑﻌد ﺣﻧوﺧذو‬ ‫‪24‬‬ ‫‪Immunoblotting‬‬ ‫ﻣﻧﺳﻣﯾﮭﺎ‪ autoradiograph‬و ‪SDS gel sample‬اﻟﻌﻣﻠﯾﺔ ﺑﯾن‬ ‫‪separation‬ﯾﻌﻧﻲ ﺑﻌد ﻣﺎ ﻋﻣﻠﻧﺎ‬ ‫ﺑﻌد ﻣﺎ ﻧﻘﻠﻧﺎھﺎ ﻋﻠﻰ اﻟورﻗﺔ‬ ‫ھﺎي ﻣﻧﺣط ﻣﺎدة ﺑﺗﻛون‬ ‫‪ regulative‬أو‬ ‫‪immunoflourscent‬‬ ‫ﻣﺷﺎن ﻧﻌﻣل ﺑﯾﮭﺎ‬ ‫‪visualiziation‬‬ ‫وﻧﺷوف اﻟﺑروﺗﯾﻧﺎت اﻟﻣوﺟودة‬ ‫أو ال‪ Antigens‬اﻟﻣوﺟودة‬ ‫ﻋﻧﺎ‬ ‫‪immunology 7105306‬‬ ‫‪25‬‬  Fc receptors ‫ اﻟﻣوﺟودات ﻋﻠﻰ اﻟﺧﻼﯾﺎ وھم‬FC receptors ‫ھون ﺑﺣﻛﻲ ﻋن‬ Phosphorylation of the ITAM motif ‫ وﻣﻧﺳﺗﻔﯾد ﻣن ارﺗﺑﺎطﮭم اﻧﮫ‬An/bodies‫اﻟﻲ ﯾرﺗﺑطوا ﺑﯾﮭم ال‬ triggers activities such as:. signaling ‫ ﻟﻠﺧﯾﻠﺔ ﻣن ﺧﻼل‬ac/va/on ‫ﺑﺻﯾر ﻋﻧﺎ‬ ‫ ﺑﺻﯾر ﻋﻧﺎ‬signaling molecules ‫ﺑﺎﻟﻧﺳﺑﺔ ﻟل‬ molecules ‫ وأﻧﺎ )اﻟدﻛﺗور( ﺑﺣﻛﻲ‬phosphorylation of ITAM motif ‫ وﻟﻣﺎ‬Activation ‫ اﺧﺗﺻﺎر ل‬ITAM ‫ ﻓﻲ‬A ‫أﺣﻔظوا اﻧﮫ ال‬ ‫ ﺑﺗﺣﻔز اﻟﺧﻠﯾﺔ وﺑﺗﺟﻌﻠﮭﺎ ﺗﺻﯾر‬ITAM‫ ﻟل‬activation ‫ﯾﺻﯾر‬ -:‫وﺣدة ﻣن اﻷﺗﯾﺎت‬ phagocytosis; antibody-dependent cell-mediated cytotoxicity (ADCC); apoptosis; mediator release; cytokines ‫زي ال‬ enhancement of antigen presentation ‫ ﺑﺻﯾر ﻣن ﺧﻼل‬inhibition ‫ ﻓﻲ ﻋﻧﺎ‬activation ‫طﺑﻌﺎ ً زي ﻣﺎ ﻓﻲ ﻋﻧﺎ‬ ‫ ﻋﻛس‬ITIM ‫ وطﺑﻌﺎ ﺑﻛون‬FC gamma 2 receptor ‫اﻟﻣﺳﺗﻘﺑﻼت ﻣﺛل‬.negative feedback ‫ ﺑﻌﻣل‬ITIM‫ و‬ITAM ‫ ﻻزم ﯾﺻﯾر إﻟﮫ‬immune response ‫ﻛﻠﻧﺎ ﻣﻧﻌرف إﻧﮫ أي‬ ‫ ﺗﺑﻌت‬mechanism ‫ ﺑﺎﻵﺧر وﺑﺻﯾر ﺑﻧﻔس ال‬termination ‫ ﺑﺗﺻﯾر ﻣن ﺧﻼل‬inhibiton‫ ﺗﺑﻌت ال‬mechanism ‫ وال‬activation FC gamma ‫ ب‬antibody ‫ ﻟﻠﺧﻠﯾﺔ إﻧﮭﺎ ﺗوﻗف ﻣن ﺧﻼل ارﺗﺑﺎط‬signals ‫ وﺑﺻﯾر ﻋﻛس اﻟﻲ‬negative Feedback ‫ واﻟﻣﺳﺗﻘﺑل ﺑﻌﻣل‬2 Receptor. activation ‫ﺻﺎر ﺑﺎل‬ immunoreceptor tyrosine-based activation (ITAM) or immunoreceptor tyrosine-based inhibitory (ITIM) FcγRI is involved in phagocytosis of immune complexes and mediator release FcγRI (CD64) binds: monomeric IgG1 and IgG3 with high affinity; relative to IgG4, low affinity; ‫ ﻣﺧﺗﻠﻔﺔ‬receptors ‫ھون ﺑس أﻣﺛﻠﺔ ﻋﻠﻰ‬ IgG2 does not have detectable binding affinity. ‫ﻛﺎﻧو ﻣﺣطوطﺎت ﺑﺟداول ﻗﺑل ﺑس ھدول ﯾﻠﻲ‬ receptor ‫ھﺎن ﺑدﻧﺎ ﻧﺣﻔظﮭم وﻧﻌرف ﻛل‬ ‫ ﯾﻠﻲ ﺑرﺑط وﺷو وظﯾﻔﺗﮫ‬antibody ‫ﻣﯾن ال‬ FcγRII is expressed in two forms ‫ وﻛﻣﺎن‬FCyRII‫ وال‬FCyRI ‫ﺑﺣﻛﯾﻠﻧﺎ ﻋن ال‬ ‫ وأﻧواﻋﮭﺎ‬FCyRIII ‫ﺑﺎﻟﺳﻼﯾد ﯾﻠﻲ ﺑﻌدھﺎ ﻋﻧﺎ ال‬ ‫اﻟﻣﺧﺗﻠﻔﺔ‬ FcγRII (CD32a; CD32b) is expressed as structurally and ‫اﻟدﻛﺗور ﺣﻛﻰ ﺑﺗﻘرأوا ھﺎي اﻟﺳﻼﯾدات ﻗراءة‬ ‫وﺑﺗﺣﻔظو اﻷﻣﺛﻠﺔ‬ functionally distinct FcγRIIa and FcγRIIb forms with wide but differing cellular distribution. The α chain of FcγRIIa: has moderate affinity for monomeric IgG1 and IgG3; binds complexed (multivalent, aggregated) IgG with high avidity; expresses an ITAM motif within its cytoplasmic tail; and may be produced as a polymorphic form which can bind monomeric IgG2. immunology 7105306 37 FcγRIII is expressed as FcγRIIIa and FcγRIIIb FcγRIIIa (CD16a) is structurally and functionally distinct from FcγRIII (CD16b) and they have different cellular distributions. Both are extensively glycosylated. FcγRIIIa is a transmembrane protein (like FcγRI, FcγRIIa, and FcγRIIb), whereas FcγRIIIb is GPI (glycosyl phosphatidyl inositol) anchored The α chains of FcγRIIIa: have a moderate affinity for monomeric IgG; and may be associated with γ/ξ and/or β chains bearing ITAM motifs. FcγRIIIa is expressed on monocytes, macrophages, NK cells, and a fraction of T cells. The FcγRIIIb form: is selectively expressed on neutrophils and basophils; and has a low affinity for monomeric IgG. immunology 7105306 38 The FcR for IgA is FcαRI FCaRI ‫ ﯾﻠﻲ ﺑرﺑط ﻋﻠﻰ ال‬IgA ‫ھون ﻛﻣﺎن ﻋﻧﺎ ال‬ low ‫ واﺣد ﺑرﺑط ب‬receptors 2 ‫ ﯾﻠﻲ اﻟﮫ‬IgE ‫وﻋﻧﺎ ال‬ The receptor for IgA is FcαRI (CD89): ‫ رح ﻧﯾﺟﻲ وﻧﺣﻛﻲ‬high affinity ‫ وواﺣد ب‬affinity it is comprised of two Ig superfamily domains; R1 ‫ﻋﻧﺎ ﻟﺑﻌدﯾن وأھﻣﯾﺗﮭم وﻣﯾن اﻟﺧﻼﯾﺎ ﯾﻠﻲ ﻣوﺟود ﻋﻠﯾﮭﺎ‬ it is associated with a γ chain; ٣‫ وﺣﻛﻰ أﻧﮫ ﻧﺣﻔظ اﻷﻣﺛﻠﺔ ﻣﻧﯾﺢ ﯾﻠﻲ ﺑﮭدول ال‬R2 ‫او‬ it is expressed on myeloid cells; ‫ﺳﻼﯾدات‬ can trigger phagocytosis, cell lysis and the release of inflammatory mediators; and can bind both IgA1 and IgA2. The two types of Fc receptor for IgE are FcεRI and FcεRII Two types of Fc receptor for IgE (FcεR) are defined in humans : the high-affinity FcεRI which is expressed on mast cells and basophils and is the ‘classical’ IgE receptor; and the low-affinity FcεRII (CD23), which is expressed on leukocytes and lymphocytes. immunology 7105306 39  Development of the antibody repertoire by gene recombination Heavy chain VDJ recombination in humans The heavy chain gene loci recombine three segments to produce a VDJ gene, which encodes the VH domain. Of some 80 V genes, about 50 are functional and the others are pseudogenes. The V gene segment recombines with one of 23 DH segments and one of six JH segments to produce a functional VDJ gene in the B cell. immunology 7105306 40  ‫‪Development of the antibody‬‬ ‫‪repertoire by gene‬‬ ‫‪recombination‬‬ ‫ﻣﻧﺳﺄل ﺣﺎﻟﻧﺎ ﻛﯾف ﻣﻧطﻘﺔ ﻣﺣددة ﻣن ال ‪ DNA,‬ﻗﺎدرة أﻧﮭﺎ ﺗﻧﺗﺞ ﻛل ﻣرة ‪ antigen binding site‬ﻣﺧﺗﻠف‬ ‫ﺑﻧﺎﺳب ال ‪ antigens‬اﻟﻣﺧﺗﻠﻔﺔ ﯾﻠﻲ ﻣﻣﻛن ﺗدﺧل ﻋﺎﻟﺟﺳم ‪ ،‬ھﺎذ اﻟﻣوﺿوع اﻻﺷﻲ اﻟرﺋﯾﺳﻲ ﯾﻠﻲ ﺑﻌﻣﻠﮫ ھو ال ‪VDJ‬‬ ‫‪ recombination,‬ﻓﺑﺣﻛﯾﻠﻧﺎ أﻧﮫ ﺑﺻﯾر ‪development of antibody repertoire by gene‬‬ ‫‪recombination,‬‬ ‫طﺑﻌﺎ ً ال ‪ gene recombination‬ﻣﻣﻛن ﺗﺻﯾر ﺑﻣﻧطﻘﺔ ال ‪ heavy chain‬وﻣﻣﻛن ﺗﺻﯾر ﺑﺎل‪light chain.‬‬ ‫ھون ﺑﮭﺎي اﻟﺻورة ﺑﺣﻛﯾﻠﻧﺎ ﻋن ال ‪ variation‬ﺑﺎل ‪heavy chain‬‬ ‫أول اﺷﻲ ﻓﻲ ﻋﻧﺎ ﻣﻧطﻘﺔ اﺳﻣﮭﺎ ال ‪V gene‬وﻣﻧطﻘﺔ اﺳﻣﮭﺎ ال ‪D gene‬وﻣﻧطﻘﺔ ال ‪J gene ،‬ھدول اﻟﻣﻧﺎطق ﻓﯾﮭم‬ ‫زي ﻗطﻊ أو ‪ fragments‬ﻣﺛﻼً ال ‪ V‬ﺑﺣﻛﯾﻠﻧﺎ ﻓﯾﮭﺎ ‪ ، genes 80‬وال ‪ D‬ﻓﯾﮭﺎ ﻣﺛﻼً ‪ ، genes 23‬وال ‪ J‬ﻋﻧﺎ ﻣﻧﮭﺎ‬ ‫‪ ,6‬ھدول ﺑﺻﯾرﻟﮭم ‪ recombination‬ﺑطرﯾﻘﺔ ﻋﺷواﺋﯾﺔ ‪ ،‬ﯾﻌﻧﻲ ﺑﺧﺗﺎر وﺣدة ﻣن ال ‪ V genes‬وﺑﻌدﯾن وﺣدة ﻣن‬ ‫ال ‪ D genes‬وآﺧر اﺷﻲ وﺣدة ﻣن ال ‪ J genes,‬وﺑﻧدﻣﺟو ﻣﻊ ﺑﻌض وﺑﺻﯾر ﻋﻧﺎ ‪ ، recombination‬ﻓﻌﻧﺎ ﺳﺑب‬ ‫ال ‪ variability‬اﻟﻌﺎﻟﯾﺔ ھو وﺟود ال ‪ fragments‬او ال ‪ segments‬ﯾﻠﻲ ﺑﺗﻌﻣل ‪. variation‬‬ ‫اذا ً ھﺎي ﺑﺳﻣوھﺎ ال ‪ VDJ recombination‬أﻧﮫ أﻛﺛر ﻣن ﺟﯾن ﺑﺷﻛﻠﻠﻧﺎ ال ‪. variable heavy domain‬‬  k chain production in humans During differentiation of the pre-B cell, one of several Vk genes on the germline DNA (V1–Vn) is recombined and apposed to a Jk segment (Jk1–Jk5). The B cell transcribes a segment of DNA into a primary RNA transcript that contains a long intervening sequence of additional J segments and introns. This transcript is processed into mRNA by splicing the exons together, and is translated by ribosomes into k chains. The rearrangement illustrated is only one of the many possible recombinations. (B cell DNA is colored light brown; RNA is colored green; and immunoglobulin peptides are colored yellow.) 41 immunology 7105306 ‫‪l chain production in humans‬‬ ‫‪k chain production in humans‬‬ ‫ﺑﺎﻟﻣﻘﺎﺑل ﻓﻲ ﻋﻧﺎ ال ‪ light chain‬وﻛﻣﺎن ﻓﻲ ﻋﻧﺎ ﻧوﻋﯾن ﻣﻧﮭﺎ ال ‪ kapa chain‬وال‬ ‫‪ lamda chain ،‬اذا ﻣﻧﺗذﻛر ﺷﻛل ال ‪ antibodies‬ﻋﻧﺎ ال ‪heavy chains‬‬ ‫اﻟطوال وﻋﻧﺎ ال ‪ light chain‬ﯾﻠﻲ ﻣﻣﻛن ﺗﻛون ‪kapa‬او ‪ ، lamda‬ھﺎد ﻋﻔﻛرة‬ ‫ﻛﻣﺎن ﻧوع ﻣن ال ‪ variations‬وﻛﻣﺎن داﺧل ﻛل وﺣدة ﻓﯾﮭم ‪ kapa‬او ‪lamda‬‬ ‫ﺑﻛون ﻧﻔس اﻟﻣﺑدأ ﯾﻠﻲ ﺣﻛﯾﻧﺎ ﻋﻧﮫ ﺑﺎﻟﺳﻼﯾد ﯾﻠﻲ ﻗﺑل ‪ ،‬ﯾﻌﻧﻲ ‪ genes‬ﺑﺻﯾرﻟﮭم‬ ‫‪ recombination‬ﻣﻊ ﺑﻌض ﺑس ﺑﻛوﻧو ‪ V‬ﻣﻊ ‪ J‬ﺑدون ‪ D‬ﻓﮭﺎي اﻟﺟﯾﻧﺎت ﺑﺗطﻠﻌﻠﻲ‬ ‫ﻛﻣﺎن ﺳﻼﺳل ‪ light chains‬ﻣﺧﺗﻠﻔﺔ ‪ ،‬طﺑﻌﺎ ً ھﺎد اﻟﺣﻛﻲ ﺑﻧطﺑق ﻋﻠﻰ ‪ kapa‬وﻛﻣﺎن‬ ‫ﻋﻠﻰ ‪ lamda‬ﯾﻠﻲ ﺑﺎﻟﺳﻼﯾد ﯾﻠﻲ ﺑﻌدھﺎ‬ l chain production in humans During B cell differentiation, one of the germline Vl genes recombines with a J segment to form a VJ combination. The rearranged gene is transcribed into a primary RNA transcript complete with introns (noncoding segments occurring between the genes), exons (which code for protein), and a poly A tail. This is spliced to form mRNA with loss of the introns, and then translated into protein. 2019-2020 Immunology 7105306 42  Recombination sequences in immunoglobulin genes light chain and heavy chain ‫ ﺑﯾن ال‬recombination ‫وﻛﻣﺎن ھون ﺑﺣﻛﯾﻠﻧﺎ أﻧﮫ ﺑﺻﯾر ﻋﻧدي‬. variation ‫ ﻟل‬source ‫ھﺎي ﺑرﺿو ﻛﻣﺎن‬ The recombination sequences in the light chain genes (top) and heavy chain genes (bottom) consist of heptamers (7), 12 or 23 unconserved bases, and nonamers (9). The sequences of heptamers and nonamers are complementary and the nonamers act as signals for the recombination activating genes to form a synapsis between the adjoining exons. Similar recombination sequences are present in the T cell receptor V, D, and J gene segments (see Chapter 5). immunology 7105306 43  Diversity is generated at several different levels Multiple V genes recombining with D and J segments VJ and VDJ recombination Recombinational inaccuracies and N-nucleotide addition Gene conversion Combination of different heavy and light chains Somatic point mutation. 2019-2020 Immunology 7105306 44  Diversity is generated at several different levels ‫ﺑﺎﻟﻣﺧﺗﺻر ﺣﺎﻛﯾﮭم ھون‬ ‫ﺳﺑﺑﮭﺎ‬antibody ‫ ﯾﻠﻲ ﺑﺗﺻﯾر ﺑﺎل‬diversity ‫ﺑﺣﻛﯾﻠﻧﺎ ال‬ J segments ‫ وال‬D ‫ ﻣﻊ ال‬multiple V genes recombining ‫ ﺑﻛون‬.1 recombination ‫ ﺑﺻﯾر‬heavy chain ‫ ﺗﺑﻌت ال‬VDJ ‫ ﻣﻊ ال‬light chain ‫ ﺗﺑﻌت ال‬VJ ‫ ﻛﻣﺎن ال‬.2 ‫ ﺟدﯾدة‬variations ‫وﺑﺗﻌﻣل‬ variation ‫ ﻟل‬source ‫ ﺑرﺿو ھﺎي‬genes ‫ ﯾﻌﻧﻲ ﺑﺻﯾر ﻗﻠب ﻟل‬gene conversion ‫ ﺑﻌدﯾن ال‬.3 light ‫ ﻻن زي ﻣﺎ ﺣﻛﯾﻧﺎ ﻋﻧﺎ ال‬combination of different heavy and light chains ‫ ﻋﻧﺎ ال‬.4 ‫ ﻋﻧﺎ ﻣﻧﮭم اﻧواع ﻛﻣﺎن ﯾﻠﻲ ھم‬heavy chains ‫ وﺑﺎﻟﻧﺳﺑﺔ ﻟل‬lamda ‫ او‬kapa ‫ﺑﺗﻛون اﻣﺎ‬chain ‫ اوﻏﯾرھم‬IgM‫ وال‬IgG ‫ال‬ ‫ ﻣن ﺧﻼل اﻟطﻔرات ﯾﻠﻲ‬improve for affinity ‫ ﯾﻠﻲ ﺑﺗﻌﻣل‬somatic hypermutation ‫ ﻋﻧﺎ‬.5 affinity‫ﺑﺗﺻﯾر وﻣﻣﻛن اﻧﮭﺎ ﺗﻛون ﻧﺎﻓﻌﺔ وﺗزﯾد ال‬ ‫ اﻟﻧﻘطﺔ اﻟﺳﺎدﺳﺔ ﺷرﺣﮭﺎ ﺑﺎﻟﺳﻼﯾد ﯾﻠﻲ ﺑﻌده‬.6 ‫‪Diversity is generated at several different levels‬‬ ‫وﻓﻲ ﻋﻧﺎ ال ‪recombinational inaccuracies‬‬ ‫‪ ، N-nucleotide addition and‬ﻟو ﻧﺗذﻛر ﺷو‬ ‫ﺷرﺣﻧﺎ ﺑﺳﻼﯾد ‪ 40‬ﻟﻣﺎ ﺣﻛﯾﻧﺎ اﻧﮫ ﺑﺻﯾر‬ ‫‪ recombination‬وﺑﻛون ﻋﻧﺎ ‪nucleotide‬‬ ‫‪ sequences‬طﯾب ﻛﯾف ھذول ﺑﺗرﺑطو ﻣﻊ ﺑﻌض ؟‬ ‫ﻓﻲ ﻋﻧﺎ اﺷﻲ اﺳﻣﮫ ال ‪ RAG‬ﯾﻠﻲ ﺑﺎﻟﺻورة ‪ ،‬ھو ﯾﻠﻲ‬ ‫ﺑﯾﺟﻲ ﺑﻛﺳر ﻗطﻊ ال ‪ V‬وال ‪ D‬وال ‪ J‬ﻋن اﻟﺳﻠﺳﻠﺔ‬ ‫ﻋﺷﺎن ﯾرﺑطﮭم ﻣﻊ ﺑﻌض ‪ ،‬ﺑس ھون ﻟﻣﺎ ﻛﺳرھم واﺟﺎ‬ ‫ﯾرﺑطﮭم ﻟﻘﻰ ﻋﻧدي ﻣﺷﻛﻠﺔ أﻧﮭم ﻣش ﻣﺗﻣﻣﺎت ﻟﺑﻌض ‪،‬‬ ‫طﯾب ﻛﯾف ﺑدﻧﺎ ﻧرﺑطﮭم ؟ ﺑﯾﺟﻲ وﺑﺿﯾف ﻧﯾوﻛﻠﯾوﺗﯾدات‬ ‫ﻣﻌﯾﻧﺔ ﻋﻠﯾﮭم ‪ ،‬ﻋﺷﺎن ﺗﺻﯾر ﻋﻧﺎ ﻋﻣﻠﯾﺔ‬ ‫ال ‪ recombination‬ﺑﯾﻧﮭم ﺗﺻﯾر ﻣﻼﺋﻣﺔ ‪ ،‬وﺑﻌدﯾن‬ ‫ﺑﯾﺟﻲ ﺑﻌﺑﻲ اﻟﻔراﻏﺎت اﻟﻣوﺟودة ﻟﺣﺗﻰ ﺗﻛﺗﻣل وھﺎذ ﻧوع‬ ‫ﻛﻣﺎن ﻣن اﻧواع ال ‪sources of variation‬‬