The Influenza Viruses

379 Pages·1968·43.17 MB·English

by  L. Hoyle

VIROLOGY
MONOGRAPHS
DIE VIRUSFORSCHUNG
IN EINZELDARSTELLUNGEN
CONTINUING /FORTFÜHRUNG VON
HANDBOOK OF VIRUS RESEARCH
HANDBUCH DER VIRUSFORSCHUNG
FOUNDED BY /BEGRÜNDET VON
R.DOERR
EDITED BY /HERAUSGEGEBEN VON
S. GARD · C. IIALLAUER · K. F. MEYER
4
1968
SPRINGER-VERLAG WIEN GMBH
THE INFLUENZA VIRUSES
BY
L. HOYLE
1968
SPRINGER-VERLAG WIEN GMBH
ISBN 978-3-7091-2048-4 ISBN 978-3-7091-2046-0 (eBook)
DOI 10.1007/978-3-7091-2046-0
All right-1:1 reservf'..d
No part of this book mny be tranl'liated or reprodueed in any form
witlwut written permission from Springer-Verlag
© 1968 by Springer-Verlag Wien
Library of Congre~s Catalog Card Number 68-54069
The Influenza Viruses
By
L. Hoyle
Director, Public Health Laboratory, Northampton, England
With 58 Figures
Table ol Contents
Preface 9
I. HistoricaJ Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
l. Isolation of the Human Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2. Neutralizatio!l and Complement Fixation . . . . . . . . . . . . . . . . . . . 10
3. The Haemagglutination Reaction . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4. Protective Vaccination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. Inhibitors of Haemagglutination . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6. Intraccllular Reproduction of the Influenza Virus . . . . . . . . . . . . 12
7. Epidemiological Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
8. Vaccination with Live Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9. A.nimal Influenza . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
10. Chemotherapy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
11. Quantitative Relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
II. Notnenclat.ure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
III. Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
L The ~fyxovirus Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2, Sub-division of the Myxovirus Group . . . . . . . . . . . . . . . . . . . . . . 19
3. Classification of the Influenza Subgroup of the Myxoviruses. . . 19
IV. Isolation of the Influenza Viruses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
l. Source of Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2. Isolation in Ferrets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3. Isolation in Mice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4. Isolation in Rat;; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5. Isolation in Hamster~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.'5
6. Isolation in EggR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7. hmlat.ion in Tist~ue CuHnres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8. U ~e. of Virus Concentmtion Method~ in Isolation . . . . . . . . . . . . . 28
9. Relative Effieie,nr·y of Variou1; 1\Iethods of Virus Isolation . . . . . 28
Virol. Monogr. 4
2 L. Hoyle: The Influenza Viruses
V. Cultivation of Influenza Viruses in Fertile Eggs . . . . . . . . . . . . . . . . . . . 28
l. Cultivation on the External Surface of the Chorioallantoic
l\fembrane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2. Cultivation in the Amniotic Sac ........ 29
0 • 0 • • • • • • • • • • • • • • • • •
~l. Cultivation in the Embryo and Yolk Sa.c . . . . . . . . . . . . . . . . . . . . . 29
4. Cultivation in the Allantoic Sac . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5. Cultivation in De-embryonated Eggs . . . . . . . . . . . . . . . . . . . . . . . 29
VI. Tissue Culture 11ethods for Influenza Virus Cultiva.tion. . . . . . . . . . . . . 30
1. Plaque )Iethods with Influenza Viruses . . . . . . . . . . . . . . . . . . . . . 32
2. Organ Cultures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
VII. Pmificat.ion of tbe Influenza Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
1. Purification by Centrifugation Methods . . . . . . . . . . . . . . . . . . . . . 33
2. Purification by Filtration Mct.hods .. , . . . . . . . . . . . . . . . . . . . . . . 34
3. Purification by Adsorption-Elution from Red Blood Cells . . . . . 34
4. Combined u~e of Adsorption-Elution from Red Cell~ and Dif-
ferential Centrifugation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5. Adsorption-Elution from Inhibitors . . . . . . . . . . . . . . . . . . . . . . . . 35
6. :-<on-specific Adsorption MethodE! . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7. Purification by Alcobol Precipitation . . . . . . . . . . . . . . . . . . . . . . . 37
8. Purification by the lJse of Ion Exchangers . . . . . . . . . . . . . . . . . . 37
9. Evaluation of Methods and Assessment of Purity . . . . . . . . . . . . 37
VIfl. Fractiouation of Influenza Virus Particlefl. . . . . . . . . . . . . . . . . . . . . . . . . 38
l. Ether Fractionation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2. Fractionat.ion by t.he Use of Detergents . . . . . . . . . . . . . . . . . . . . 39
3. Comhined 'Cse of Dctergents and Ether . . . . . . . . . . . . . . . . . . . . 40
4. Otber :\lethods nf Disruption .. _ . _ . . . . . . . . . . . . . . . . . . . . . . . . . 40
IX. Chemical Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
l. Ji'atty and Lipid Constitucnts of the Virus. . . . . . . . . . . . . . . . . . . 41
2. Polysaccharide Con;;tituents of the Virus . . . . . . . . . . . . . . . . . . . . 41
3. Protein Componenl.s of thc Virus. . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4. Thc ViriL~ );'ucleic Acid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5. Radioactive LabeHingof Influenza Virul'\ . . . . . . . . . . . . . . . . . . . 45
X. Antigenie Structure ....................... , ........ , . . . . . . . . . . 46
l. The S Antigen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2. The V Antigen Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
:~. The H ofil Antigen ComponentH . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
XI. Morphology and Physieal St.rueture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
l. Size of t.he Influenza Viruse;.; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
2. Electron }lieroKeopy - Shadow Ca~;ting Teehnique,; . . . . . . . . . 52
:l. C~lofm!"r, FibrnentouH and Bizarre l•'orrnfi of Virus .... , . . . . . . 52
4. Eleet.ron .\licro,;eopy hy t.he ;-..; eglttive ~t.aining Technique . . . . . 5!!
:;, l\lorphology of Virm; Fmction~. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
fi. l'h.v~ir·al b;tnwture of l.hc Viru;.; l'artielfl . . . . . . . . . . . . . . . . . . . . 63
7. w~~ight, Den;.;ity. Vo lume and \Vater Cou1.ent of the Viru>;
ParLiek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (j7
H. Corwlm;iow-< . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Table of Contents 3
XII. Resistance to Physical and Chemical Agents . . . . . . . . . . . . . . . . . . . . . . 68
l. Heat Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
2. Resistance to Freezing and Thawing. . . . . . . . . . . . . . . . . . . . . . . . 69
3. Re&istance to Drying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4. Resistance to Ultrasonic Vibration . . . . . . . . . . . . . . . . . . . . . . . . 70
5. Resistance to pH Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6. Effect of Ions on Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
7. Resista.nce to Ionising Radia.tions . . . . . . . . . . . . . . . . . . . . . . . . . . 70
8. Resistance to Chemical Agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
9. Survival and Resistance of Influenza Virus in Air . . . . . . . . . . . . 7 4
10. Inactivation of Yaccines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
XUI. The Infective Property of the Influenza Viruses . . . . . . . . . . . . . . . . . . . 75
l. lnfectivity Titration in Mice. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
2. lnfectivity Titration in Fertile Eggs . . . . . . . . . . . . . . . . . . . . . . . i7
3. lnfectivity Titration in Tissne Cultures . . . . . . . . . . . . . . . . . . . . . 78
4. Infectivity of Influenza Virus Ribonucleic Acid . . . . . . . . . . . . . . 79
5. Some Reflections on the Nature of the Infecting Property of
Influenza Viruses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
XIV. Haemagglutination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
l. The Salk Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
2. Dcnsitometric Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
3. Other .M:cthods of Haemagglutinin Titration . . . . . . . . . . . . . . . . 83
4. Effect of pH, Tempemture and Salt Goncentration on Haem-
agglutination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5. Mechanism of the IL!.emagglutination Reaction . . . . . . . . . . . . . . 84
6. Effcct of Virus on Lhe Red Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
7. Nature oE the Red Cell Receptors . . . . . . . . . . . . . . . . . . . . . . . . . . 87
8. Agglutination of Red Cells of Different Animal Species . . . . . . . 88
9. Relation bctween the Number of Virus Particles Present. in a
ViruB Suspension and the Jla.emagglut.inin Titre. . . . . . . . . . . . . . 89
XV. Enzymic Activity of Influenza ViruReil . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
l. Nature of the Virus Rceeptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
2. 'l'he Reeeptor Destroying Enzyme of V. d10lerae, RDE . . . . . . . 91
3. Estimat.ion of Neuraminidase Aetivity . . . . . . . . . . . . . . . . . . . . . 91
4. J\.lechanism of Nemaminidase Action . . . . . . . . . . . . . . . . . . . . . . . 92
5. Purification of Viruil Neuraminirla~e . . . . . . . . . . . . . . . . . . . . . . . ()·)
6. Variations in t.he Neumminidase Aetiviiy of Different ::'tmins
of Virus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
7. Relation of Neurnminidasc to Haemagglut.inin . . . . . . . . . . . . . . 93
8. Relu,tion of Neuraminidase to t.lw Virus Growth Cyde . . . . . . . . 94
XVI. Inhibitors of Hacmagglutirmtion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
l. 'l'he Frauci<> or ~ Inhibitor"... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9;)
2. The Chu or ß Inhibitor>' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
3. Ot.her Type~ of Ilamna,gglntiniu luhibit.or~ in Serum . . . . . . . . . !)8
4. Eledrophorcti<' Analyc;iH of Serum Inhihüors . . . . . . . . . . . . . . . . 98
5. Na,ture of the Non-speeifi<· Inhihit.on; of Normal Sera 119
4 L. Hoyle: The Influenza Viruses
XVII. Serological Rea.ctions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
A. Serologkai Reactions of the Inner Ribonueleoprotein Componeut .. 100
l. The Group Complement Fixation Test ..................... 100
2. Teclmique and e~e of the Group Complement Fixation Reaction 101
3. Precipitin Reactions with the SAntigen .................... 103
4. Specificity of the S Antigen ............................... 103
B. Serological Reactiou~ of thc Outer Virus Component ............ 104
l. The N eutralization Te8t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
2. Quantitative X eutralization Te~ts in Mice 104
:J. Quantitative X entralization rrest.s in Eggs .................. 105
4. Neutralization in Tissue Cultures .......................... 105
5. ~Iecha.nism of the X eutralization Reaction . . . . . . . . . . . . . . . . . . 106
6. The Haemagglutination-inhibition Test ..................... 107
i. Destruction of Xon·specific Inhibitors in Serum ............. 108
8. Antigenie Analysi,;; by the Use of I! I Tests ............. , .... 109
9. The Specific Cornplement FixfLtion Test .................... llO
10. Technique of the Specific Complement Fixation Test . . . . . . . . . llO
11, Agglutination, Pre<'ipitation and Flocculation Test'! .......... 111
12. Precipitin Reactiou~ by the Gel-diffusion Technique ......... 112
13. Antibody Abwrption 'l'eehuiques . . . . . . . . . . . . . . . . . . . . . . . . . . 112
14. Relation between Xcutralizing, Haemagglutinin-inhibiting,
Speeific Cornplement l<'ixing and Preeipii.ating Antibodies .... 113
X\' III. Growth Cyele of the Influenza Virus - General Dcscription ......... 114
1. Sorrw Quantitative Considerations . . . . . . . . . . . . . . . . . . . . . . . . . 115
2. Intraeellulfl.r Reproduction of thc Influenza Viruses . . . . . . . . . . 116
XIX. Stage,.; in t.he Growth Cycle of Infh<enzfl. Viruses ................... ll8
A. Initial Union of Viru~ with the Cell: Adsorption Stage ........... 118
1. Effcet;; of Rerept.or Destruction by RDE ................... 120
2. Effeds of Immune Serum on Virus Adsorption .............. 121
:l. Effects of Ilaemagglutinin Inhibitor;~ ....................... 121
4. Effe,~ts uf Receptor.blocking Agents ......................• 121
fi. Summary of the ObKervationH on Initial Union of Virus with
the Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
ll. Stage of J'mtet mtion and EclipHe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
1. Electron )licroH,~ope StudieH of the Pemltration of Virus intu
the Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
2. Sturlies of t1w l'nnetration St.a.ge by tllfl lJAe of Radioactive
Tracers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12ti
:1. Effect of Rihonudea~;e on Viruf\ Produdion ................. 127
4. Chewi•~al Inhibition of l'enetration and Ec!ipKe .............. 127
fi. Analysifi of the l'erwtration a.wl Eclipse Stages ............. 128
<:. The lntranudear l'IH1Ht1 ..................................... 12H
l. 1-itudieH with Fluoreseent Ant.ibody ...................... , . 129
2 . .Nuclear 1-iynthe~i~ of Virus ll.~ A .......................... 129
:L 'l'ht• JY~ A -dependenee oE Virus Synt.hnsis ................... 130
4. The l'lii1110Hll•non of ":\Iu.ltiplidt.y-depetHlent. Delay" ......... l:H
Table of Contents 5
5. Infection with Damaged RNA ............................ 131
6. Size of the Infecting RNA 1\lolecule ........................ 132
7. Pm11lible Synthesis of V Antigen Fracursors in the Cell Kudeus 133
D. The Cytoplasmic Phase ..................................... 133
1. Morphology and Properties of Intracellular Haemagglutinin . . . 135
2. Intracellular Synthesis of Ncuraminidase ................... 136
3. State of the Cytoplasmic SAntigen ........................ 137
4. Cytoplasmic Inclusion Bodies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
E. Stage of Maturation and Release ............................. 137
I. :Microscopical Observations on the Release of Influenza Virus
from the Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
2. Assembly of Virus Components ............................ 138
3. Relation of Neurarninidase to Virus Release ................. 140
}'. The Biochemical J<:vents in Influenza Virus Reproduction ....... 140
I. ZHDANov's Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
2. Early Biochemical Events in Influenza Virus Reproduction .. 141
3. Synthesis of Virus RNA .................................. 142
4. Theory of Synthesis Based on the Use of Cell DNA .......... 143
5. Possible Fragmentation and Re-assembly of Virus RNA ...... 143
6. Asscmbly of Virus Components at the Cell Sudace ........... 144
7. Surnmary ............................................... 144
XX. Incomplete Growth Cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
I. Failure to Excrete Infective Virus from t.he Cell ............. 144
2. Production of Extracellular Ineomplete Virus - the VON
~lAGNUS Phenomenon .................................... 146
3. Analysis of the VON MAGNUS Phenomenon. . . . . . . . . . . . . . . . . . . 148
4. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
XXI. The Interference Phenomenon in Influenza Virus lnfection ......... 151
I. Interference betweeu Influenza and Unrelated Vin1ses ........ 151
2. Interference between Live Influenza Virus Straim ........... 151
3. Interferenoo Produced by Inactivated Virus ................. 153
4. Interference in the Chick Chorion .......................... 154
5. Interference in Mouse Brain Tissue ........................ 155
6. llechanism of the Interference Pilenornenon ................ 155
7. Interferon .............................................. 155
8. General Diseuseion of the Interferenee Plwnomenon . . . . . . . . . 158
XXII. Influenza Virus Genetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
A. The Reaetivation Phenomenon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
I. Multiplicity Reactivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
2. Reactivation by Heterologou8 Virus . . . . . . . . . . . . . . . . . . . . . . . 160
3. Re~~ctivation of Fowl P1ague Virus ......................... 160
4. Rcactivation and Vaccine Production ...................... 161
B. The Recombination Phenomenon ............................. 161
1. Marker Characteristics and the 8election of Pure Clones . . . . . . 161
2. The Rccombination Phcnomenon . . . . . . . . . . . . . . . . . . . . . . . . . . 162
3. Produetion of Doubly Neutralisahle Reeornbinant Strains ..... 163
6 L. Hoyle: The Influenza Viruses
4. Phenotypic )Iixing, lleterozygosis and Diploidy 164
5. Geneties of Virulence in Influenza Viruses .................. 165
6. Recombination Experiments with Plaque-forming Strains ..... 166
7. Rapid Adaptation of Viruses as a Result of Recombination. . . . 168
8. Effect of Ribonuclease on Recombination . . . . . . . . . . . . . . . . . . . 168
9. Use of Recombination in Production of Vaccine Strains ...... 168
C. Gencra.l Discussion of Influenza Virus Geneties . . . . . . . . . . . . . . . . . 168
XXIII. Adaptation and Variation in Influenzf1 Viruses .................... 169
A. Adaptation ................................................ 169
l. Adaptation of Virus to Ferrets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
2. Adaptation of Virus to ::VIice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
3. Adaptation to Hamsters and Other Anima.ls . . . . . . . . . . . . . . . . . 171
4. Adaptation to the Chick Embryo Chorion .................. 172
5. Adaptation to Growtb in Brain Tissue - Neurotropic Variants 172
6. Adaptation to Growth in the Allantoic Sac - the 0-D Vari-
ation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
B. Variation ................................................. 174
l. Variations in Haenmgglutinin Production during Adaptation 174
2. Variations in Inhibitor Sensitivity and Enzymic Activity ... 175
3. Variation in Antigenie Structure .......................... 177
4. Experimental l'roduction of Changes in Antigenie Structure . . 179
5. The P-Q-R Variation .................................... 181
6. Antigenie Variation with Virus B .......................... 182
7. Variation in ResiBtance to Physical and Chemical Agents ..... 182
C. General Consideraiion of the Phenomena of Adaptation and Vari
ation in Influenza Viruses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
XXIV. The Toxic l'roperties of Influenza Viruse.'l ........................ 184
l. The N eurotoxic J-'roperty ................................. li-!5
2. Toxic Effeet11 Producer! by Intravenous anrl Intra-peritoneal
Inoculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
3. The Pyrogenic Effect of Influenza Virusm;. . . . . . . . . . . . . . . . . . . 187
4. Other i\fanife~tations of Virus Toxicity . . . . . . . . . . . . . . . . . . . . . 18.'1
5. Nature of the Taxie Component of the Virus Particle ........ 189
XXV. Clinical Feature~ and Pathology of Influenza ......... , ........... 189
I. Relation of the Clinical Dit>ease to the Propertiell of ihe Virus 190
2. l'athology ot' Influenza ................................... l!H
XX V I. .\letaholiflm of the lnfcded Cell in Influenza ...................... 197
XXVII. Lahoratory DiagnosiH of Influenza ............................... 201
A. Isolation and Identifieat.ion of Virus .......................... 201
B. ~erologiea1 DiagnoHis ....................................... 201
C. Rapid l\letl1ods of L;tboratory Diagnosis ...................... 204
XX VIII. lrnmunity anti Antibody Prod~etion in Influenza ................. 205
l. 1\atural lmrnunity to lnfluenr.al Infection .................. 205
2. Aequired lrnrnunit.y ...................................... 20G